abstract class AsyncFreeSpec extends AsyncFreeSpecLike
Enables testing of asynchronous code without blocking,
using a style consistent with traditional AnyFreeSpec
tests.
Recommended Usage:
AsyncFreeSpec is intended to enable users of AnyFreeSpec
to write non-blocking asynchronous tests that are consistent with their traditional AnyFreeSpec tests.
Note: AsyncFreeSpec is intended for use in special situations where non-blocking asynchronous
testing is needed, with class AnyFreeSpec used for general needs.
|
Given a Future
returned by the code you are testing,
you need not block until the Future
completes before
performing assertions against its value. You can instead map those
assertions onto the Future
and return the resulting
Future[Assertion]
to ScalaTest. The test will complete
asynchronously, when the Future[Assertion]
completes.
Here's an example AsyncFreeSpec
:
package org.scalatest.examples.asyncfreespec
import org.scalatest.freespec.AsyncFreeSpec import scala.concurrent.Future
class AddSpec extends AsyncFreeSpec {
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"addSoon" - { "will eventually compute a sum of passed Ints" in { val futureSum: Future[Int] = addSoon(1, 2) // You can map assertions onto a Future, then return // the resulting Future[Assertion] to ScalaTest: futureSum map { sum => assert(sum == 3) } } }
def addNow(addends: Int*): Int = addends.sum
"addNow" - { "will immediately compute a sum of passed Ints" in { val sum: Int = addNow(1, 2) // You can also write synchronous tests. The body // must have result type Assertion: assert(sum == 3) } } }
In an AsyncFreeSpec
you write a test with a string followed by in
and the body of the
test in curly braces, like this:
"will eventually compute a sum of passed Ints" in { // ... }
You can nest a test inside any number of description clauses, which you write with a string followed by a dash character and a block, like this:
"addSoon" - { // ... }
You can nest description clauses as deeply as you want. Because the description clause is denoted with an operator, not
a word like should
, you are free to structure the text however you wish.
In short, you structure an AsyncFreeSpec
exactly like a AnyFreeSpec
, but with
tests having result type Assertion
or Future[Assertion]
. For more examples
of structure, see the documentation for AnyFreeSpec
.
Starting with version 3.0.0, ScalaTest assertions and matchers have result type Assertion
.
The result type of the first test in the example above, therefore, is Future[Assertion]
.
For clarity, here's the relevant code in a REPL session:
scala> import org.scalatest._ import org.scalatest._ scala> import Assertions._ import Assertions._ scala> import scala.concurrent.Future import scala.concurrent.Future scala> import scala.concurrent.ExecutionContext import scala.concurrent.ExecutionContext scala> implicit val executionContext = ExecutionContext.Implicits.global executionContext: scala.concurrent.ExecutionContextExecutor = scala.concurrent.impl.ExecutionContextImpl@26141c5b scala> def addSoon(addends: Int*): Future[Int] = Future { addends.sum } addSoon: (addends: Int*)scala.concurrent.Future[Int] scala> val futureSum: Future[Int] = addSoon(1, 2) futureSum: scala.concurrent.Future[Int] = scala.concurrent.impl.Promise$DefaultPromise@721f47b2 scala> futureSum map { sum => assert(sum == 3) } res0: scala.concurrent.Future[org.scalatest.Assertion] = scala.concurrent.impl.Promise$DefaultPromise@3955cfcb
The second test has result type Assertion
:
scala> def addNow(addends: Int*): Int = addends.sum addNow: (addends: Int*)Int scala> val sum: Int = addNow(1, 2) sum: Int = 3 scala> assert(sum == 3) res1: org.scalatest.Assertion = Succeeded
When AddSpec
is constructed, the second test will be implicitly converted to
Future[Assertion]
and registered. The implicit conversion is from Assertion
to Future[Assertion]
, so you must end synchronous tests in some ScalaTest assertion
or matcher expression. If a test would not otherwise end in type Assertion
, you can
place succeed
at the end of the test. succeed
, a field in trait Assertions
,
returns the Succeeded
singleton:
scala> succeed res2: org.scalatest.Assertion = Succeeded
Thus placing succeed
at the end of a test body will satisfy the type checker:
"will immediately compute a sum of passed Ints" - { val sum: Int = addNow(1, 2) assert(sum == 3) println("hi") // println has result type Unit succeed // succeed has result type Assertion }
An AsyncFreeSpec
's lifecycle has two phases: the registration phase and the
ready phase. It starts in registration phase and enters ready phase the first time
run
is called on it. It then remains in ready phase for the remainder of its lifetime.
Tests can only be registered with the it
method while the AsyncFreeSpec
is
in its registration phase. Any attempt to register a test after the AsyncFreeSpec
has
entered its ready phase, i.e., after run
has been invoked on the AsyncFreeSpec
,
will be met with a thrown TestRegistrationClosedException
. The recommended style
of using AsyncFreeSpec
is to register tests during object construction as is done in all
the examples shown here. If you keep to the recommended style, you should never see a
TestRegistrationClosedException
.
Asynchronous execution model
AsyncFreeSpec
extends AsyncTestSuite
, which provides an
implicit scala.concurrent.ExecutionContext
named executionContext
. This
execution context is used by AsyncFreeSpec
to
transform the Future[Assertion]
s returned by each test
into the FutureOutcome
returned by the test
function
passed to withFixture
.
This ExecutionContext
is also intended to be used in the tests,
including when you map assertions onto futures.
On both the JVM and Scala.js, the default execution context provided by ScalaTest's asynchronous
testing styles confines execution to a single thread per test. On JavaScript, where single-threaded
execution is the only possibility, the default execution context is
scala.scalajs.concurrent.JSExecutionContext.Implicits.queue
. On the JVM,
the default execution context is a serial execution context provided by ScalaTest itself.
When ScalaTest's serial execution context is called upon to execute a task, that task is recorded
in a queue for later execution. For example, one task that will be placed in this queue is the
task that transforms the Future[Assertion]
returned by an asynchronous test body
to the FutureOutcome
returned from the test
function.
Other tasks that will be queued are any transformations of, or callbacks registered on, Future
s that occur
in your test body, including any assertions you map onto Future
s. Once the test body returns,
the thread that executed the test body will execute the tasks in that queue one after another, in the order they
were enqueued.
ScalaTest provides its serial execution context as the default on the JVM for three reasons. First, most often
running both tests and suites in parallel does not give a significant performance boost compared to
just running suites in parallel. Thus parallel execution of Future
transformations within
individual tests is not generally needed for performance reasons.
Second, if multiple threads are operating in the same suite
concurrently, you'll need to make sure access to any mutable fixture objects by multiple threads is synchronized.
Although access to mutable state along
the same linear chain of Future
transformations need not be synchronized,
this does not hold true for callbacks, and in general it is easy to make a mistake. Simply put: synchronizing access to
shared mutable state is difficult and error prone.
Because ScalaTest's default execution context on the JVM confines execution of Future
transformations
and call backs to a single thread, you need not (by default) worry about synchronizing access to mutable state
in your asynchronous-style tests.
Third, asynchronous-style tests need not be complete when the test body returns, because the test body returns
a Future[Assertion]
. This Future[Assertion]
will often represent a test that has not yet
completed. As a result, when using a more traditional execution context backed by a thread-pool, you could
potentially start many more tests executing concurrently than there are threads in the thread pool. The more
concurrently execute tests you have competing for threads from the same limited thread pool, the more likely it
will be that tests will intermitently fail due to timeouts.
Using ScalaTest's serial execution context on the JVM will ensure the same thread that produced the Future[Assertion]
returned from a test body is also used to execute any tasks given to the execution context while executing the test
body—and that thread will not be allowed to do anything else until the test completes.
If the serial execution context's task queue ever becomes empty while the Future[Assertion]
returned by
that test's body has not yet completed, the thread will block until another task for that test is enqueued. Although
it may seem counter-intuitive, this blocking behavior means the total number of tests allowed to run concurrently will be limited
to the total number of threads executing suites. This fact means you can tune the thread pool such that maximum performance
is reached while avoiding (or at least, reducing the likelihood of) tests that fail due to timeouts because of thread competition.
This thread confinement strategy does mean, however, that when you are using the default execution context on the JVM, you
must be sure to never block in the test body waiting for a task to be completed by the
execution context. If you block, your test will never complete. This kind of problem will be obvious, because the test will
consistently hang every time you run it. (If a test is hanging, and you're not sure which one it is,
enable slowpoke notifications.) If you really do
want to block in your tests, you may wish to just use a
traditional AnyFreeSpec
with
ScalaFutures
instead. Alternatively, you could override
the executionContext
and use a traditional ExecutionContext
backed by a thread pool. This
will enable you to block in an asynchronous-style test on the JVM, but you'll need to worry about synchronizing access to
shared mutable state.
To use a different execution context, just override executionContext
. For example, if you prefer to use
the runNow
execution context on Scala.js instead of the default queue
, you would write:
// on Scala.js implicit override def executionContext = org.scalatest.concurrent.TestExecutionContext.runNow
If you prefer on the JVM to use the global execution context, which is backed by a thread pool, instead of ScalaTest's default serial execution contex, which confines execution to a single thread, you would write:
// on the JVM (and also compiles on Scala.js, giving // you the queue execution context) implicit override def executionContext = scala.concurrent.ExecutionContext.Implicits.global
Serial and parallel test execution
By default (unless you mix in ParallelTestExecution
), tests in an AsyncFreeSpec
will be executed one after
another, i.e., serially. This is true whether those tests return Assertion
or Future[Assertion]
,
no matter what threads are involved. This default behavior allows
you to re-use a shared fixture, such as an external database that needs to be cleaned
after each test, in multiple tests in async-style suites. This is implemented by registering each test, other than the first test, to run
as a continuation after the previous test completes.
If you want the tests of an AsyncFreeSpec
to be executed in parallel, you
must mix in ParallelTestExecution
and enable parallel execution of tests in your build.
You enable parallel execution in Runner
with the -P
command line flag.
In the ScalaTest Maven Plugin, set parallel
to true
.
In sbt
, parallel execution is the default, but to be explicit you can write:
parallelExecution in Test := true // the default in sbt
On the JVM, if both ParallelTestExecution
is mixed in and
parallel execution is enabled in the build, tests in an async-style suite will be started in parallel, using threads from
the Distributor
, and allowed to complete in parallel, using threads from the
executionContext
. If you are using ScalaTest's serial execution context, the JVM default, asynchronous tests will
run in parallel very much like traditional (such as AnyFreeSpec
) tests run in
parallel: 1) Because ParallelTestExecution
extends
OneInstancePerTest
, each test will run in its own instance of the test class, you need not worry about synchronizing
access to mutable instance state shared by different tests in the same suite.
2) Because the serial execution context will confine the execution of each test to the single thread that executes the test body,
you need not worry about synchronizing access to shared mutable state accessed by transformations and callbacks of Future
s
inside the test.
If ParallelTestExecution
is mixed in but
parallel execution of suites is not enabled, asynchronous tests on the JVM will be started sequentially, by the single thread
that invoked run
, but without waiting for one test to complete before the next test is started. As a result,
asynchronous tests will be allowed to complete in parallel, using threads
from the executionContext
. If you are using the serial execution context, however, you'll see
the same behavior you see when parallel execution is disabled and a traditional suite that mixes in ParallelTestExecution
is executed: the tests will run sequentially. If you use an execution context backed by a thread-pool, such as global
,
however, even though tests will be started sequentially by one thread, they will be allowed to run concurrently using threads from the
execution context's thread pool.
The latter behavior is essentially what you'll see on Scala.js when you execute a suite that mixes in ParallelTestExecution
.
Because only one thread exists when running under JavaScript, you can't "enable parallel execution of suites." However, it may
still be useful to run tests in parallel on Scala.js, because tests can invoke API calls that are truly asynchronous by calling into
external APIs that take advantage of non-JavaScript threads. Thus on Scala.js, ParallelTestExecution
allows asynchronous
tests to run in parallel, even though they must be started sequentially. This may give you better performance when you are using API
calls in your Scala.js tests that are truly asynchronous.
Futures and expected exceptions
If you need to test for expected exceptions in the context of futures, you can use the
recoverToSucceededIf
and recoverToExceptionIf
methods of trait
RecoverMethods
. Because this trait is mixed into
supertrait AsyncTestSuite
, both of these methods are
available by default in an AsyncFreeSpec
.
If you just want to ensure that a future fails with a particular exception type, and do
not need to inspect the exception further, use recoverToSucceededIf
:
recoverToSucceededIf[IllegalStateException] { // Result type: Future[Assertion] emptyStackActor ? Peek }
The recoverToSucceededIf
method performs a job similar to
assertThrows
, except
in the context of a future. It transforms a Future
of any type into a
Future[Assertion]
that succeeds only if the original future fails with the specified
exception. Here's an example in the REPL:
scala> import org.scalatest.RecoverMethods._ import org.scalatest.RecoverMethods._ scala> import scala.concurrent.Future import scala.concurrent.Future scala> import scala.concurrent.ExecutionContext.Implicits.global import scala.concurrent.ExecutionContext.Implicits.global scala> recoverToSucceededIf[IllegalStateException] { | Future { throw new IllegalStateException } | } res0: scala.concurrent.Future[org.scalatest.Assertion] = ... scala> res0.value res1: Option[scala.util.Try[org.scalatest.Assertion]] = Some(Success(Succeeded))
Otherwise it fails with an error message similar to those given by assertThrows
:
scala> recoverToSucceededIf[IllegalStateException] { | Future { throw new RuntimeException } | } res2: scala.concurrent.Future[org.scalatest.Assertion] = ... scala> res2.value res3: Option[scala.util.Try[org.scalatest.Assertion]] = Some(Failure(org.scalatest.exceptions.TestFailedException: Expected exception java.lang.IllegalStateException to be thrown, but java.lang.RuntimeException was thrown)) scala> recoverToSucceededIf[IllegalStateException] { | Future { 42 } | } res4: scala.concurrent.Future[org.scalatest.Assertion] = ... scala> res4.value res5: Option[scala.util.Try[org.scalatest.Assertion]] = Some(Failure(org.scalatest.exceptions.TestFailedException: Expected exception java.lang.IllegalStateException to be thrown, but no exception was thrown))
The recoverToExceptionIf
method differs from the recoverToSucceededIf
in
its behavior when the assertion succeeds: recoverToSucceededIf
yields a Future[Assertion]
,
whereas recoverToExceptionIf
yields a Future[T]
, where T
is the
expected exception type.
recoverToExceptionIf[IllegalStateException] { // Result type: Future[IllegalStateException] emptyStackActor ? Peek }
In other words, recoverToExpectionIf
is to
intercept
as
recovertToSucceededIf
is to assertThrows
. The first one allows you to
perform further assertions on the expected exception. The second one gives you a result type that will satisfy the type checker
at the end of the test body. Here's an example showing recoverToExceptionIf
in the REPL:
scala> val futureEx = | recoverToExceptionIf[IllegalStateException] { | Future { throw new IllegalStateException("hello") } | } futureEx: scala.concurrent.Future[IllegalStateException] = ... scala> futureEx.value res6: Option[scala.util.Try[IllegalStateException]] = Some(Success(java.lang.IllegalStateException: hello)) scala> futureEx map { ex => assert(ex.getMessage == "world") } res7: scala.concurrent.Future[org.scalatest.Assertion] = ... scala> res7.value res8: Option[scala.util.Try[org.scalatest.Assertion]] = Some(Failure(org.scalatest.exceptions.TestFailedException: "[hello]" did not equal "[world]"))
Ignored tests
To support the common use case of temporarily disabling a test, with the
good intention of resurrecting the test at a later time, AsyncFreeSpec
adds a method
ignore
to strings that can be used instead of in
to register a test. For example, to temporarily
disable the test with the name "addSoon will eventually compute a sum of passed Ints"
, just
change “in
” into “ignore
,” like this:
package org.scalatest.examples.asyncfreespec.ignore
import org.scalatest.freespec.AsyncFreeSpec import scala.concurrent.Future
class AddSpec extends AsyncFreeSpec {
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"addSoon" - { "will eventually compute a sum of passed Ints" ignore { val futureSum: Future[Int] = addSoon(1, 2) // You can map assertions onto a Future, then return // the resulting Future[Assertion] to ScalaTest: futureSum map { sum => assert(sum == 3) } } }
def addNow(addends: Int*): Int = addends.sum
"addNow" - { "will immediately compute a sum of passed Ints" in { val sum: Int = addNow(1, 2) // You can also write synchronous tests. The body // must have result type Assertion: assert(sum == 3) } } }
If you run this version of AddSpec
with:
scala> org.scalatest.run(new AddSpec)
It will run only the second test and report that the first test was ignored:
AddSpec: addSoon - will eventually compute a sum of passed Ints !!! IGNORED !!! addNow - will immediately compute a sum of passed Ints
If you wish to temporarily ignore an entire suite of tests, you can (on the JVM, not Scala.js) annotate the test class with @Ignore
, like this:
package org.scalatest.examples.asyncfreespec.ignoreall
import org.scalatest.freespec.AsyncFreeSpec import scala.concurrent.Future import org.scalatest.Ignore
@Ignore class AddSpec extends AsyncFreeSpec {
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"addSoon" - { "will eventually compute a sum of passed Ints" in { val futureSum: Future[Int] = addSoon(1, 2) // You can map assertions onto a Future, then return // the resulting Future[Assertion] to ScalaTest: futureSum map { sum => assert(sum == 3) } } }
def addNow(addends: Int*): Int = addends.sum
"addNow" - { "will immediately compute a sum of passed Ints" in { val sum: Int = addNow(1, 2) // You can also write synchronous tests. The body // must have result type Assertion: assert(sum == 3) } } }
When you mark a test class with a tag annotation, ScalaTest will mark each test defined in that class with that tag.
Thus, marking the AddSpec
in the above example with the @Ignore
tag annotation means that both tests
in the class will be ignored. If you run the above AddSpec
in the Scala interpreter, you'll see:
AddSpec: addSoon - will eventually compute a sum of passed Ints !!! IGNORED !!! addNow - will immediately compute a sum of passed Ints !!! IGNORED !!!
Note that marking a test class as ignored won't prevent it from being discovered by ScalaTest. Ignored classes
will be discovered and run, and all their tests will be reported as ignored. This is intended to keep the ignored
class visible, to encourage the developers to eventually fix and “un-ignore” it. If you want to
prevent a class from being discovered at all (on the JVM, not Scala.js), use the DoNotDiscover
annotation instead.
If you want to ignore all tests of a suite on Scala.js, where annotations can't be inspected at runtime, you'll need
to change it
to ignore
at each test site. To make a suite non-discoverable on Scala.js, ensure it
does not declare a public no-arg constructor. You can either declare a public constructor that takes one or more
arguments, or make the no-arg constructor non-public. Because this technique will also make the suite non-discoverable
on the JVM, it is a good approach for suites you want to run (but not be discoverable) on both Scala.js and the JVM.
Informers
One of the parameters to AsyncFreeSpec
's run
method is a Reporter
, which
will collect and report information about the running suite of tests.
Information about suites and tests that were run, whether tests succeeded or failed,
and tests that were ignored will be passed to the Reporter
as the suite runs.
Most often the reporting done by default by AsyncFreeSpec
's methods will be sufficient, but
occasionally you may wish to provide custom information to the Reporter
from a test.
For this purpose, an Informer
that will forward information to the current Reporter
is provided via the info
parameterless method.
You can pass the extra information to the Informer
via its apply
method.
The Informer
will then pass the information to the Reporter
via an InfoProvided
event.
One use case for the Informer
is to pass more information about a specification to the reporter. For example,
the GivenWhenThen
trait provides methods that use the implicit info
provided by AsyncFreeSpec
to pass such information to the reporter. Here's an example:
package org.scalatest.examples.asyncfreespec.info
import collection.mutable import org.scalatest._
class SetSpec extends freespec.AsyncFreeSpec with GivenWhenThen {
"A mutable Set" - { "should allow an element to be added" in { Given("an empty mutable Set") val set = mutable.Set.empty[String]
When("an element is added") set += "clarity"
Then("the Set should have size 1") assert(set.size === 1)
And("the Set should contain the added element") assert(set.contains("clarity"))
info("That's all folks!") succeed } } }
If you run this AsyncFreeSpec
from the interpreter, you will see the following output:
scala> org.scalatest.run(new SetSpec)
A mutable Set
- should allow an element to be added
+ Given an empty mutable Set
+ When an element is added
+ Then the Set should have size 1
+ And the Set should contain the added element
+ That's all folks!
Documenters
AsyncFreeSpec
also provides a markup
method that returns a Documenter
, which allows you to send
to the Reporter
text formatted in Markdown syntax.
You can pass the extra information to the Documenter
via its apply
method.
The Documenter
will then pass the information to the Reporter
via an MarkupProvided
event.
Here's an example AsyncFreeSpec
that uses markup
:
package org.scalatest.examples.asyncfreespec.markup
import collection.mutable import org.scalatest._
class SetSpec extends freespec.AsyncFreeSpec with GivenWhenThen {
markup { """ Mutable Set ———-- A set is a collection that contains no duplicate elements. To implement a concrete mutable set, you need to provide implementations of the following methods: def contains(elem: A): Boolean def iterator: Iterator[A] def += (elem: A): this.type def -= (elem: A): this.type If you wish that methods like `take`, `drop`, `filter` return the same kind of set, you should also override: def empty: This It is also good idea to override methods `foreach` and `size` for efficiency. """ }
"A mutable Set" - { "should allow an element to be added" in { Given("an empty mutable Set") val set = mutable.Set.empty[String]
When("an element is added") set += "clarity"
Then("the Set should have size 1") assert(set.size === 1)
And("the Set should contain the added element") assert(set.contains("clarity"))
markup("This test finished with a **bold** statement!") succeed } } }
Although all of ScalaTest's built-in reporters will display the markup text in some form,
the HTML reporter will format the markup information into HTML. Thus, the main purpose of markup
is to
add nicely formatted text to HTML reports. Here's what the above SetSpec
would look like in the HTML reporter:
Notifiers and alerters
ScalaTest records text passed to info
and markup
during tests, and sends the recorded text in the recordedEvents
field of
test completion events like TestSucceeded
and TestFailed
. This allows string reporters (like the standard out reporter) to show
info
and markup
text after the test name in a color determined by the outcome of the test. For example, if the test fails, string
reporters will show the info
and markup
text in red. If a test succeeds, string reporters will show the info
and markup
text in green. While this approach helps the readability of reports, it means that you can't use info
to get status
updates from long running tests.
To get immediate (i.e., non-recorded) notifications from tests, you can use note
(a Notifier
) and alert
(an Alerter
). Here's an example showing the differences:
package org.scalatest.examples.asyncfreespec.note
import collection.mutable import org.scalatest._
class SetSpec extends freespec.AsyncFreeSpec {
"A mutable Set" - { "should allow an element to be added" in {
info("info is recorded") markup("markup is *also* recorded") note("notes are sent immediately") alert("alerts are also sent immediately")
val set = mutable.Set.empty[String] set += "clarity" assert(set.size === 1) assert(set.contains("clarity")) } } }
scala> org.scalatest.run(new SetSpec) SetSpec: A mutable Set + notes are sent immediately + alerts are also sent immediately - should allow an element to be added + info is recorded + markup is *also* recorded
Another example is slowpoke notifications.
If you find a test is taking a long time to complete, but you're not sure which test, you can enable
slowpoke notifications. ScalaTest will use an Alerter
to fire an event whenever a test has been running
longer than a specified amount of time.
In summary, use info
and markup
for text that should form part of the specification output. Use
note
and alert
to send status notifications. (Because the HTML reporter is intended to produce a
readable, printable specification, info
and markup
text will appear in the HTML report, but
note
and alert
text will not.)
Pending tests
A pending test is one that has been given a name but is not yet implemented. The purpose of pending tests is to facilitate a style of testing in which documentation of behavior is sketched out before tests are written to verify that behavior (and often, before the behavior of the system being tested is itself implemented). Such sketches form a kind of specification of what tests and functionality to implement later.
To support this style of testing, a test can be given a name that specifies one
bit of behavior required by the system being tested. At the end of the test,
it can call method pending
, which will cause it to complete abruptly with TestPendingException
.
Because tests in ScalaTest can be designated as pending with TestPendingException
, both the test name and any information
sent to the reporter when running the test can appear in the report of a test run. (In other words,
the code of a pending test is executed just like any other test.) However, because the test completes abruptly
with TestPendingException
, the test will be reported as pending, to indicate
the actual test, and possibly the functionality, has not yet been implemented. Here's an example:
package org.scalatest.examples.asyncfreespec.pending
import org.scalatest.freespec.AsyncFreeSpec import scala.concurrent.Future
class AddSpec extends AsyncFreeSpec {
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"addSoon" - { "will eventually compute a sum of passed Ints" in (pending) }
def addNow(addends: Int*): Int = addends.sum
"addNow" - { "will immediately compute a sum of passed Ints" in { val sum: Int = addNow(1, 2) // You can also write synchronous tests. The body // must have result type Assertion: assert(sum == 3) } } }
(Note: "(pending)
" is the body of the test. Thus the test contains just one statement, an invocation
of the pending
method, which throws TestPendingException
.)
If you run this version of AddSpec
with:
scala> org.scalatest.run(new AddSpec)
It will run both tests, but report that first test is pending. You'll see:
AddSpec: addSoon - will eventually compute a sum of passed Ints (pending) addNow - will immediately compute a sum of passed Ints
One difference between an ignored test and a pending one is that an ignored test is intended to be used during significant refactorings of the code under test, when tests break and you don't want to spend the time to fix all of them immediately. You can mark some of those broken tests as ignored temporarily, so that you can focus the red bar on just failing tests you actually want to fix immediately. Later you can go back and fix the ignored tests. In other words, by ignoring some failing tests temporarily, you can more easily notice failed tests that you actually want to fix. By contrast, a pending test is intended to be used before a test and/or the code under test is written. Pending indicates you've decided to write a test for a bit of behavior, but either you haven't written the test yet, or have only written part of it, or perhaps you've written the test but don't want to implement the behavior it tests until after you've implemented a different bit of behavior you realized you need first. Thus ignored tests are designed to facilitate refactoring of existing code whereas pending tests are designed to facilitate the creation of new code.
One other difference between ignored and pending tests is that ignored tests are implemented as a test tag that is
excluded by default. Thus an ignored test is never executed. By contrast, a pending test is implemented as a
test that throws TestPendingException
(which is what calling the pending
method does). Thus
the body of pending tests are executed up until they throw TestPendingException
.
Tagging tests
An AsyncFreeSpec
's tests may be classified into groups by tagging them with string names.
As with any suite, when executing an AsyncFreeSpec
, groups of tests can
optionally be included and/or excluded. To tag an AsyncFreeSpec
's tests,
you pass objects that extend class org.scalatest.Tag
to methods
that register tests. Class Tag
takes one parameter, a string name. If you have
created tag annotation interfaces as described in the Tag
documentation, then you
will probably want to use tag names on your test functions that match. To do so, simply
pass the fully qualified names of the tag interfaces to the Tag
constructor. For example, if you've
defined a tag annotation interface with fully qualified name,
com.mycompany.tags.DbTest
, then you could
create a matching tag for AsyncFreeSpec
s like this:
package org.scalatest.examples.asyncfreespec.tagging
import org.scalatest.Tag
object DbTest extends Tag("com.mycompany.tags.DbTest")
Given these definitions, you could place AsyncFreeSpec
tests into groups with tags like this:
import org.scalatest.freespec.AsyncFreeSpec import org.scalatest.tagobjects.Slow import scala.concurrent.Future
class AddSpec extends AsyncFreeSpec {
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"addSoon" - { "will eventually compute a sum of passed Ints" taggedAs(Slow) in { val futureSum: Future[Int] = addSoon(1, 2) // You can map assertions onto a Future, then return // the resulting Future[Assertion] to ScalaTest: futureSum map { sum => assert(sum == 3) } } }
def addNow(addends: Int*): Int = addends.sum
"addNow" - { "will immediately compute a sum of passed Ints" taggedAs(Slow, DbTest) in {
val sum: Int = addNow(1, 2) // You can also write synchronous tests. The body // must have result type Assertion: assert(sum == 3) } } }
This code marks both tests with the org.scalatest.tags.Slow
tag,
and the second test with the com.mycompany.tags.DbTest
tag.
The run
method takes a Filter
, whose constructor takes an optional
Set[String]
called tagsToInclude
and a Set[String]
called
tagsToExclude
. If tagsToInclude
is None
, all tests will be run
except those those belonging to tags listed in the
tagsToExclude
Set
. If tagsToInclude
is defined, only tests
belonging to tags mentioned in the tagsToInclude
set, and not mentioned in tagsToExclude
,
will be run.
It is recommended, though not required, that you create a corresponding tag annotation when you
create a Tag
object. A tag annotation (on the JVM, not Scala.js) allows you to tag all the tests of an AsyncFreeSpec
in
one stroke by annotating the class. For more information and examples, see the
documentation for class Tag
. On Scala.js, to tag all tests of a suite, you'll need to
tag each test individually at the test site.
Shared fixtures
A test fixture is composed of the objects and other artifacts (files, sockets, database connections, etc.) tests use to do their work. When multiple tests need to work with the same fixtures, it is important to try and avoid duplicating the fixture code across those tests. The more code duplication you have in your tests, the greater drag the tests will have on refactoring the actual production code.
ScalaTest recommends three techniques to eliminate such code duplication in async styles:
- Refactor using Scala
- Override
withFixture
- Mix in a before-and-after trait
Each technique is geared towards helping you reduce code duplication without introducing
instance var
s, shared mutable objects, or other dependencies between tests. Eliminating shared
mutable state across tests will make your test code easier to reason about and eliminate the need to
synchronize access to shared mutable state on the JVM.
The following sections describe these techniques, including explaining the recommended usage for each. But first, here's a table summarizing the options:
Refactor using Scala when different tests need different fixtures. | |
get-fixture methods | The extract method refactor helps you create a fresh instances of mutable fixture objects in each test that needs them, but doesn't help you clean them up when you're done. |
loan-fixture methods | Factor out dupicate code with the loan pattern when different tests need different fixtures that must be cleaned up afterwards. |
Override withFixture when most or all tests need the same fixture.
|
|
withFixture(NoArgAsyncTest)
|
The recommended default approach when most or all tests need the same fixture treatment. This general technique
allows you, for example, to perform side effects at the beginning and end of all or most tests,
transform the outcome of tests, retry tests, make decisions based on test names, tags, or other test data.
Use this technique unless:
|
withFixture(OneArgAsyncTest)
|
Use when you want to pass the same fixture object or objects as a parameter into all or most tests. |
Mix in a before-and-after trait when you want an aborted suite, not a failed test, if the fixture code fails. | |
BeforeAndAfter
|
Use this boilerplate-buster when you need to perform the same side-effects before and/or after tests, rather than at the beginning or end of tests. |
BeforeAndAfterEach
|
Use when you want to stack traits that perform the same side-effects before and/or after tests, rather than at the beginning or end of tests. |
Calling get-fixture methods
If you need to create the same mutable fixture objects in multiple tests, and don't need to clean them up after using them, the simplest approach is to write one or more get-fixture methods. A get-fixture method returns a new instance of a needed fixture object (or a holder object containing multiple fixture objects) each time it is called. You can call a get-fixture method at the beginning of each test that needs the fixture, storing the returned object or objects in local variables. Here's an example:
package org.scalatest.examples.asyncfreespec.getfixture
import org.scalatest.freespec.AsyncFreeSpec import scala.concurrent.Future
class ExampleSpec extends AsyncFreeSpec {
def fixture: Future[String] = Future { "ScalaTest is " }
"Testing" - { "should be easy" in { val future = fixture val result = future map { s => s + "easy!" } result map { s => assert(s == "ScalaTest is easy!") } }
"should be fun" in { val future = fixture val result = future map { s => s + "fun!" } result map { s => assert(s == "ScalaTest is fun!") } } } }
If you need to configure fixture objects differently in different tests, you can pass configuration into the get-fixture method. For example, you could pass in an initial value for a fixture object as a parameter to the get-fixture method.
Overriding withFixture(NoArgAsyncTest)
Although the get-fixture method approach takes care of setting up a fixture at the beginning of each
test, it doesn't address the problem of cleaning up a fixture at the end of the test. If you just need to perform a side-effect at the beginning or end of
a test, and don't need to actually pass any fixture objects into the test, you can override withFixture(NoArgAsyncTest)
, a
method defined in trait AsyncTestSuite
, a supertrait of AsyncFreeSpec
.
Trait AsyncFreeSpec
's runTest
method passes a no-arg async test function to
withFixture(NoArgAsyncTest)
. It is withFixture
's
responsibility to invoke that test function. The default implementation of withFixture
simply
invokes the function and returns the result, like this:
// Default implementation in trait AsyncTestSuite protected def withFixture(test: NoArgAsyncTest): FutureOutcome = { test() }
You can, therefore, override withFixture
to perform setup before invoking the test function,
and/or perform cleanup after the test completes. The recommended way to ensure cleanup is performed after a test completes is
to use the complete
-lastly
syntax, defined in supertrait CompleteLastly
.
The complete
-lastly
syntax will ensure that
cleanup will occur whether future-producing code completes abruptly by throwing an exception, or returns
normally yielding a future. In the latter case, complete
-lastly
will register the cleanup code
to execute asynchronously when the future completes.
The withFixture
method is designed to be stacked, and to enable this, you should always call the super
implementation
of withFixture
, and let it invoke the test function rather than invoking the test function directly. In other words, instead of writing
“test()
”, you should write “super.withFixture(test)
”, like this:
// Your implementation override def withFixture(test: NoArgAsyncTest) = {
// Perform setup here
complete { super.withFixture(test) // Invoke the test function } lastly { // Perform cleanup here } }
If you have no cleanup to perform, you can write withFixture
like this instead:
// Your implementation override def withFixture(test: NoArgAsyncTest) = {
// Perform setup here
super.withFixture(test) // Invoke the test function }
If you want to perform an action only for certain outcomes, you'll need to
register code performing that action as a callback on the Future
using
one of Future
's registration methods: onComplete
, onSuccess
,
or onFailure
. Note that if a test fails, that will be treated as a
scala.util.Success(org.scalatest.Failed)
. So if you want to perform an
action if a test fails, for example, you'd register the callback using onSuccess
.
Here's an example in which withFixture(NoArgAsyncTest)
is used to take a
snapshot of the working directory if a test fails, and
send that information to the standard output stream:
package org.scalatest.examples.asyncfreespec.noargasynctest
import java.io.File import org.scalatest._ import scala.concurrent.Future
class ExampleSpec extends freespec.AsyncFreeSpec {
override def withFixture(test: NoArgAsyncTest) = {
super.withFixture(test) onFailedThen { _ => val currDir = new File(".") val fileNames = currDir.list() info("Dir snapshot: " + fileNames.mkString(", ")) } }
def addSoon(addends: Int*): Future[Int] = Future { addends.sum }
"This test" - { "should succeed" in { addSoon(1, 1) map { sum => assert(sum == 2) } }
"should fail" in { addSoon(1, 1) map { sum => assert(sum == 3) } } } }
Running this version of ExampleSpec
in the interpreter in a directory with two files, hello.txt
and world.txt
would give the following output:
scala> org.scalatest.run(new ExampleSpec) ExampleSpec: This test - should succeed - should fail *** FAILED *** 2 did not equal 3 (:33)
Note that the NoArgAsyncTest
passed to withFixture
, in addition to
an apply
method that executes the test, also includes the test name and the config
map passed to runTest
. Thus you can also use the test name and configuration objects in your withFixture
implementation.
Lastly, if you want to transform the outcome in some way in withFixture
, you'll need to use either the
map
or transform
methods of Future
, like this:
// Your implementation override def withFixture(test: NoArgAsyncTest) = {
// Perform setup here
val futureOutcome = super.withFixture(test) // Invoke the test function
futureOutcome change { outcome => // transform the outcome into a new outcome here } }
Note that a NoArgAsyncTest
's apply
method will return a scala.util.Failure
only if
the test completes abruptly with a "test-fatal" exception (such as OutOfMemoryError
) that should
cause the suite to abort rather than the test to fail. Thus usually you would use map
to transform future outcomes, not transform
, so that such test-fatal exceptions pass through
unchanged. The suite will abort asynchronously with any exception returned from NoArgAsyncTest
's
apply method in a scala.util.Failure
.
Calling loan-fixture methods
If you need to both pass a fixture object into a test and perform cleanup at the end of the test, you'll need to use the loan pattern. If different tests need different fixtures that require cleanup, you can implement the loan pattern directly by writing loan-fixture methods. A loan-fixture method takes a function whose body forms part or all of a test's code. It creates a fixture, passes it to the test code by invoking the function, then cleans up the fixture after the function returns.
The following example shows three tests that use two fixtures, a database and a file. Both require cleanup after, so each is provided via a
loan-fixture method. (In this example, the database is simulated with a StringBuffer
.)
package org.scalatest.examples.asyncfreespec.loanfixture
import java.util.concurrent.ConcurrentHashMap
import scala.concurrent.Future import scala.concurrent.ExecutionContext
object DbServer { // Simulating a database server type Db = StringBuffer private final val databases = new ConcurrentHashMap[String, Db] def createDb(name: String): Db = { val db = new StringBuffer // java.lang.StringBuffer is thread-safe databases.put(name, db) db } def removeDb(name: String): Unit = { databases.remove(name) } }
// Defining actor messages sealed abstract class StringOp case object Clear extends StringOp case class Append(value: String) extends StringOp case object GetValue
class StringActor { // Simulating an actor private final val sb = new StringBuilder def !(op: StringOp): Unit = synchronized { op match { case Append(value) => sb.append(value) case Clear => sb.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[String] = Future { synchronized { sb.toString } } }
import org.scalatest._ import DbServer._ import java.util.UUID.randomUUID
class ExampleSpec extends freespec.AsyncFreeSpec {
def withDatabase(testCode: Future[Db] => Future[Assertion]) = { val dbName = randomUUID.toString // generate a unique db name val futureDb = Future { createDb(dbName) } // create the fixture complete { val futurePopulatedDb = futureDb map { db => db.append("ScalaTest is ") // perform setup } testCode(futurePopulatedDb) // "loan" the fixture to the test code } lastly { removeDb(dbName) // ensure the fixture will be cleaned up } }
def withActor(testCode: StringActor => Future[Assertion]) = { val actor = new StringActor complete { actor ! Append("ScalaTest is ") // set up the fixture testCode(actor) // "loan" the fixture to the test code } lastly { actor ! Clear // ensure the fixture will be cleaned up } }
"Testing" - { // This test needs the actor fixture "should be productive" in { withActor { actor => actor ! Append("productive!") val futureString = actor ? GetValue futureString map { s => assert(s == "ScalaTest is productive!") } } } }
"Test code" - { // This test needs the database fixture "should be readable" in { withDatabase { futureDb => futureDb map { db => db.append("readable!") assert(db.toString == "ScalaTest is readable!") } } }
// This test needs both the actor and the database "should be clear and concise" in { withDatabase { futureDb => withActor { actor => // loan-fixture methods compose actor ! Append("concise!") val futureString = actor ? GetValue val futurePair: Future[(Db, String)] = futureDb zip futureString futurePair map { case (db, s) => db.append("clear!") assert(db.toString == "ScalaTest is clear!") assert(s == "ScalaTest is concise!") } } } } } }
As demonstrated by the last test, loan-fixture methods compose. Not only do loan-fixture methods allow you to give each test the fixture it needs, they allow you to give a test multiple fixtures and clean everything up afterwards.
Also demonstrated in this example is the technique of giving each test its own "fixture sandbox" to play in. When your fixtures involve external side-effects, like creating databases, it is a good idea to give each database a unique name as is done in this example. This keeps tests completely isolated, allowing you to run them in parallel if desired.
Overriding withFixture(OneArgTest)
If all or most tests need the same fixture, you can avoid some of the boilerplate of the loan-fixture method approach by using a
FixtureAsyncTestSuite
and overriding withFixture(OneArgAsyncTest)
.
Each test in a FixtureAsyncTestSuite
takes a fixture as a parameter, allowing you to pass the fixture into
the test. You must indicate the type of the fixture parameter by specifying FixtureParam
, and implement a
withFixture
method that takes a OneArgAsyncTest
. This withFixture
method is responsible for
invoking the one-arg async test function, so you can perform fixture set up before invoking and passing
the fixture into the test function, and ensure clean up is performed after the test completes.
To enable the stacking of traits that define withFixture(NoArgAsyncTest)
, it is a good idea to let
withFixture(NoArgAsyncTest)
invoke the test function instead of invoking the test
function directly. To do so, you'll need to convert the OneArgAsyncTest
to a NoArgAsyncTest
. You can do that by passing
the fixture object to the toNoArgAsyncTest
method of OneArgAsyncTest
. In other words, instead of
writing “test(theFixture)
”, you'd delegate responsibility for
invoking the test function to the withFixture(NoArgAsyncTest)
method of the same instance by writing:
withFixture(test.toNoArgAsyncTest(theFixture))
Here's a complete example:
package org.scalatest.examples.asyncfreespec.oneargasynctest
import org.scalatest._ import scala.concurrent.Future import scala.concurrent.ExecutionContext
// Defining actor messages sealed abstract class StringOp case object Clear extends StringOp case class Append(value: String) extends StringOp case object GetValue
class StringActor { // Simulating an actor private final val sb = new StringBuilder def !(op: StringOp): Unit = synchronized { op match { case Append(value) => sb.append(value) case Clear => sb.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[String] = Future { synchronized { sb.toString } } }
class ExampleSpec extends freespec.FixtureAsyncFreeSpec {
type FixtureParam = StringActor
def withFixture(test: OneArgAsyncTest): FutureOutcome = {
val actor = new StringActor complete { actor ! Append("ScalaTest is ") // set up the fixture withFixture(test.toNoArgAsyncTest(actor)) } lastly { actor ! Clear // ensure the fixture will be cleaned up } }
"Testing" - { "should be easy" in { actor => actor ! Append("easy!") val futureString = actor ? GetValue futureString map { s => assert(s == "ScalaTest is easy!") } }
"should be fun" in { actor => actor ! Append("fun!") val futureString = actor ? GetValue futureString map { s => assert(s == "ScalaTest is fun!") } } } }
In this example, the tests required one fixture object, a StringActor
. If your tests need multiple fixture objects, you can
simply define the FixtureParam
type to be a tuple containing the objects or, alternatively, a case class containing
the objects. For more information on the withFixture(OneArgAsyncTest)
technique, see
the documentation for FixtureAsyncFreeSpec
.
Mixing in BeforeAndAfter
In all the shared fixture examples shown so far, the activities of creating, setting up, and cleaning up the fixture objects have been
performed during the test. This means that if an exception occurs during any of these activities, it will be reported as a test failure.
Sometimes, however, you may want setup to happen before the test starts, and cleanup after the test has completed, so that if an
exception occurs during setup or cleanup, the entire suite aborts and no more tests are attempted. The simplest way to accomplish this in ScalaTest is
to mix in trait BeforeAndAfter
. With this trait you can denote a bit of code to run before each test
with before
and/or after each test each test with after
, like this:
package org.scalatest.examples.asyncfreespec.beforeandafter
import org.scalatest.freespec.AsyncFreeSpec import org.scalatest.BeforeAndAfter import scala.concurrent.Future import scala.concurrent.ExecutionContext
// Defining actor messages sealed abstract class StringOp case object Clear extends StringOp case class Append(value: String) extends StringOp case object GetValue
class StringActor { // Simulating an actor private final val sb = new StringBuilder def !(op: StringOp): Unit = synchronized { op match { case Append(value) => sb.append(value) case Clear => sb.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[String] = Future { synchronized { sb.toString } } }
class ExampleSpec extends AsyncFreeSpec with BeforeAndAfter {
final val actor = new StringActor
before { actor ! Append("ScalaTest is ") // set up the fixture }
after { actor ! Clear // clean up the fixture }
"Testing" - { "should be easy" in { actor ! Append("easy!") val futureString = actor ? GetValue futureString map { s => assert(s == "ScalaTest is easy!") } }
"should be fun" in { actor ! Append("fun!") val futureString = actor ? GetValue futureString map { s => assert(s == "ScalaTest is fun!") } } } }
Note that the only way before
and after
code can communicate with test code is via some
side-effecting mechanism, commonly by reassigning instance var
s or by changing the state of mutable
objects held from instance val
s (as in this example). If using instance var
s or
mutable objects held from instance val
s you wouldn't be able to run tests in parallel in the same instance
of the test class (on the JVM, not Scala.js) unless you synchronized access to the shared, mutable state.
Note that on the JVM, if you override ScalaTest's default
serial execution context, you will likely need to
worry about synchronizing access to shared mutable fixture state, because the execution
context may assign different threads to process
different Future
transformations. Although access to mutable state along
the same linear chain of Future
transformations need not be synchronized,
it can be difficult to spot cases where these constraints are violated. The best approach
is to use only immutable objects when transforming Future
s. When that's not
practical, involve only thread-safe mutable objects, as is done in the above example.
On Scala.js, by contrast, you need not worry about thread synchronization, because
in effect only one thread exists.
Although BeforeAndAfter
provides a minimal-boilerplate way to execute code before and after tests, it isn't designed to enable stackable
traits, because the order of execution would be non-obvious. If you want to factor out before and after code that is common to multiple test suites, you
should use trait BeforeAndAfterEach
instead, as shown later in the next section,
composing fixtures by stacking traits.
Composing fixtures by stacking traits
In larger projects, teams often end up with several different fixtures that test classes need in different combinations,
and possibly initialized (and cleaned up) in different orders. A good way to accomplish this in ScalaTest is to factor the individual
fixtures into traits that can be composed using the stackable trait pattern. This can be done, for example, by placing
withFixture
methods in several traits, each of which call super.withFixture
. Here's an example in
which the StringBuilderActor
and StringBufferActor
fixtures used in the previous examples have been
factored out into two stackable fixture traits named Builder
and Buffer
:
package org.scalatest.examples.asyncfreespec.composingwithasyncfixture
import org.scalatest._ import org.scalatest.SuiteMixin import collection.mutable.ListBuffer import scala.concurrent.Future import scala.concurrent.ExecutionContext
// Defining actor messages sealed abstract class StringOp case object Clear extends StringOp case class Append(value: String) extends StringOp case object GetValue
class StringBuilderActor { // Simulating an actor private final val sb = new StringBuilder def !(op: StringOp): Unit = synchronized { op match { case Append(value) => sb.append(value) case Clear => sb.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[String] = Future { synchronized { sb.toString } } }
class StringBufferActor { private final val buf = ListBuffer.empty[String] def !(op: StringOp): Unit = synchronized { op match { case Append(value) => buf += value case Clear => buf.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[List[String]] = Future { synchronized { buf.toList } } }
trait Builder extends AsyncTestSuiteMixin { this: AsyncTestSuite =>
final val builderActor = new StringBuilderActor
abstract override def withFixture(test: NoArgAsyncTest) = { builderActor ! Append("ScalaTest is ") complete { super.withFixture(test) // To be stackable, must call super.withFixture } lastly { builderActor ! Clear } } }
trait Buffer extends AsyncTestSuiteMixin { this: AsyncTestSuite =>
final val bufferActor = new StringBufferActor
abstract override def withFixture(test: NoArgAsyncTest) = { complete { super.withFixture(test) // To be stackable, must call super.withFixture } lastly { bufferActor ! Clear } } }
class ExampleSpec extends freespec.AsyncFreeSpec with Builder with Buffer {
"Testing" - { "should be easy" in { builderActor ! Append("easy!") val futureString = builderActor ? GetValue val futureList = bufferActor ? GetValue val futurePair: Future[(String, List[String])] = futureString zip futureList futurePair map { case (str, lst) => assert(str == "ScalaTest is easy!") assert(lst.isEmpty) bufferActor ! Append("sweet") succeed } }
"should be fun" in { builderActor ! Append("fun!") val futureString = builderActor ? GetValue val futureList = bufferActor ? GetValue val futurePair: Future[(String, List[String])] = futureString zip futureList futurePair map { case (str, lst) => assert(str == "ScalaTest is fun!") assert(lst.isEmpty) bufferActor ! Append("awesome") succeed } } } }
By mixing in both the Builder
and Buffer
traits, ExampleSpec
gets both fixtures, which will be
initialized before each test and cleaned up after. The order the traits are mixed together determines the order of execution.
In this case, Builder
is “super” to Buffer
. If you wanted Buffer
to be “super”
to Builder
, you need only switch the order you mix them together, like this:
class Example2Spec extends freespec.AsyncFreeSpec with Buffer with Builder
If you only need one fixture you mix in only that trait:
class Example3Spec extends freespec.AsyncFreeSpec with Builder
Another way to create stackable fixture traits is by extending the BeforeAndAfterEach
and/or BeforeAndAfterAll
traits.
BeforeAndAfterEach
has a beforeEach
method that will be run before each test (like JUnit's setUp
),
and an afterEach
method that will be run after (like JUnit's tearDown
).
Similarly, BeforeAndAfterAll
has a beforeAll
method that will be run before all tests,
and an afterAll
method that will be run after all tests. Here's what the previously shown example would look like if it
were rewritten to use the BeforeAndAfterEach
methods instead of withFixture
:
package org.scalatest.examples.asyncfreespec.composingbeforeandaftereach
import org.scalatest._ import org.scalatest.BeforeAndAfterEach import collection.mutable.ListBuffer import scala.concurrent.Future import scala.concurrent.ExecutionContext
// Defining actor messages sealed abstract class StringOp case object Clear extends StringOp case class Append(value: String) extends StringOp case object GetValue
class StringBuilderActor { // Simulating an actor private final val sb = new StringBuilder def !(op: StringOp): Unit = synchronized { op match { case Append(value) => sb.append(value) case Clear => sb.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[String] = Future { synchronized { sb.toString } } }
class StringBufferActor { private final val buf = ListBuffer.empty[String] def !(op: StringOp): Unit = synchronized { op match { case Append(value) => buf += value case Clear => buf.clear() } } def ?(get: GetValue.type)(implicit c: ExecutionContext): Future[List[String]] = Future { synchronized { buf.toList } } }
trait Builder extends BeforeAndAfterEach { this: Suite =>
final val builderActor = new StringBuilderActor
override def beforeEach() { builderActor ! Append("ScalaTest is ") super.beforeEach() // To be stackable, must call super.beforeEach }
override def afterEach() { try super.afterEach() // To be stackable, must call super.afterEach finally builderActor ! Clear } }
trait Buffer extends BeforeAndAfterEach { this: Suite =>
final val bufferActor = new StringBufferActor
override def afterEach() { try super.afterEach() // To be stackable, must call super.afterEach finally bufferActor ! Clear } }
class ExampleSpec extends freespec.AsyncFreeSpec with Builder with Buffer {
"Testing" - {
"should be easy" in { builderActor ! Append("easy!") val futureString = builderActor ? GetValue val futureList = bufferActor ? GetValue val futurePair: Future[(String, List[String])] = futureString zip futureList futurePair map { case (str, lst) => assert(str == "ScalaTest is easy!") assert(lst.isEmpty) bufferActor ! Append("sweet") succeed } }
"should be fun" in { builderActor ! Append("fun!") val futureString = builderActor ? GetValue val futureList = bufferActor ? GetValue val futurePair: Future[(String, List[String])] = futureString zip futureList futurePair map { case (str, lst) => assert(str == "ScalaTest is fun!") assert(lst.isEmpty) bufferActor ! Append("awesome") succeed } } } }
To get the same ordering as withFixture
, place your super.beforeEach
call at the end of each
beforeEach
method, and the super.afterEach
call at the beginning of each afterEach
method, as shown in the previous example. It is a good idea to invoke super.afterEach
in a try
block and perform cleanup in a finally
clause, as shown in the previous example, because this ensures the
cleanup code is performed even if super.afterEach
throws an exception.
The difference between stacking traits that extend BeforeAndAfterEach
versus traits that implement withFixture
is
that setup and cleanup code happens before and after the test in BeforeAndAfterEach
, but at the beginning and
end of the test in withFixture
. Thus if a withFixture
method completes abruptly with an exception, it is
considered a failed test. By contrast, if any of the beforeEach
or afterEach
methods of BeforeAndAfterEach
complete abruptly, it is considered an aborted suite, which will result in a SuiteAborted
event.
Shared tests
Sometimes you may want to run the same test code on different fixture objects. In other words, you may want to write tests that are "shared"
by different fixture objects.
To accomplish this in an AsyncFreeSpec
, you first place shared tests in
behavior functions. These behavior functions will be
invoked during the construction phase of any AsyncFreeSpec
that uses them, so that the tests they contain will
be registered as tests in that AsyncFreeSpec
.
For example, given this StackActor
class:
package org.scalatest.examples.asyncfreespec.sharedtests
import scala.collection.mutable.ListBuffer import scala.concurrent.Future import scala.concurrent.ExecutionContext
// Stack operations case class Push[T](value: T) sealed abstract class StackOp case object Pop extends StackOp case object Peek extends StackOp case object Size extends StackOp
// Stack info case class StackInfo[T](top: Option[T], size: Int, max: Int) { require(size > 0, "size was less than zero") require(max >= size, "max was less than size") val isFull: Boolean = size == max val isEmpty: Boolean = size == 0 }
class StackActor[T](Max: Int, name: String) {
private final val buf = new ListBuffer[T]
def !(push: Push[T]): Unit = synchronized { if (buf.size != Max) buf.prepend(push.value) else throw new IllegalStateException("can't push onto a full stack") }
def ?(op: StackOp)(implicit c: ExecutionContext): Future[StackInfo[T]] = synchronized { op match { case Pop => Future { if (buf.size != 0) StackInfo(Some(buf.remove(0)), buf.size, Max) else throw new IllegalStateException("can't pop an empty stack") } case Peek => Future { if (buf.size != 0) StackInfo(Some(buf(0)), buf.size, Max) else throw new IllegalStateException("can't peek an empty stack") } case Size => Future { StackInfo(None, buf.size, Max) } } }
override def toString: String = name }
You may want to test the stack represented by the StackActor
class in different states: empty, full, with one item, with one item less than capacity,
etc. You may find you have several tests that make sense any time the stack is non-empty. Thus you'd ideally want to run
those same tests for three stack fixture objects: a full stack, a stack with a one item, and a stack with one item less than
capacity. With shared tests, you can factor these tests out into a behavior function, into which you pass the
stack fixture to use when running the tests. So in your AsyncFreeSpec
for StackActor
, you'd invoke the
behavior function three times, passing in each of the three stack fixtures so that the shared tests are run for all three fixtures.
You can define a behavior function that encapsulates these shared tests inside the AsyncFreeSpec
that uses them. If they are shared
between different AsyncFreeSpec
s, however, you could also define them in a separate trait that is mixed into
each AsyncFreeSpec
that uses them.
For example, here the nonEmptyStackActor
behavior function (in this case, a
behavior method) is defined in a trait along with another
method containing shared tests for non-full stacks:
import org.scalatest.freespec.AsyncFreeSpec
trait AsyncFreeSpecStackBehaviors { this: AsyncFreeSpec =>
def nonEmptyStackActor(createNonEmptyStackActor: => StackActor[Int], lastItemAdded: Int, name: String): Unit = {
("return non-empty StackInfo when Size is fired at non-empty stack actor: " + name) in { val stackActor = createNonEmptyStackActor val futureStackInfo = stackActor ? Size futureStackInfo map { stackInfo => assert(!stackInfo.isEmpty) } }
("return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: " + name) in { val stackActor = createNonEmptyStackActor val futurePair: Future[(StackInfo[Int], StackInfo[Int])] = for { beforePeek <- stackActor ? Size afterPeek <- stackActor ? Peek } yield (beforePeek, afterPeek) futurePair map { case (beforePeek, afterPeek) => assert(afterPeek.top == Some(lastItemAdded)) assert(afterPeek.size == beforePeek.size) } }
("return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: " + name) in { val stackActor = createNonEmptyStackActor val futurePair: Future[(StackInfo[Int], StackInfo[Int])] = for { beforePop <- stackActor ? Size afterPop <- stackActor ? Pop } yield (beforePop, afterPop) futurePair map { case (beforePop, afterPop) => assert(afterPop.top == Some(lastItemAdded)) assert(afterPop.size == beforePop.size - 1) } } }
def nonFullStackActor(createNonFullStackActor: => StackActor[Int], name: String): Unit = {
("return non-full StackInfo when Size is fired at non-full stack actor: " + name) in { val stackActor = createNonFullStackActor val futureStackInfo = stackActor ? Size futureStackInfo map { stackInfo => assert(!stackInfo.isFull) } }
("return before and after StackInfo that has existing size + 1 and new item as top when Push is fired at non-full stack actor: " + name) in { val stackActor = createNonFullStackActor val futurePair: Future[(StackInfo[Int], StackInfo[Int])] = for { beforePush <- stackActor ? Size afterPush <- { stackActor ! Push(7); stackActor ? Peek } } yield (beforePush, afterPush) futurePair map { case (beforePush, afterPush) => assert(afterPush.top == Some(7)) assert(afterPush.size == beforePush.size + 1) } } } }
Given these behavior functions, you could invoke them directly, but AsyncFreeSpec
offers a DSL for the purpose,
which looks like this:
behave like nonEmptyStackActor(almostEmptyStackActor, LastValuePushed, almostEmptyStackActorName)
Here's an example:
class StackSpec extends AsyncFreeSpec with AsyncFreeSpecStackBehaviors {
val Max = 10 val LastValuePushed = Max - 1
// Stack fixture creation methods val emptyStackActorName = "empty stack actor" def emptyStackActor = new StackActor[Int](Max, emptyStackActorName )
val fullStackActorName = "full stack actor" def fullStackActor = { val stackActor = new StackActor[Int](Max, fullStackActorName ) for (i <- 0 until Max) stackActor ! Push(i) stackActor }
val almostEmptyStackActorName = "almost empty stack actor" def almostEmptyStackActor = { val stackActor = new StackActor[Int](Max, almostEmptyStackActorName ) stackActor ! Push(LastValuePushed) stackActor }
val almostFullStackActorName = "almost full stack actor" def almostFullStackActor = { val stackActor = new StackActor[Int](Max, almostFullStackActorName) for (i <- 1 to LastValuePushed) stackActor ! Push(i) stackActor }
"A Stack" - { "(when empty)" - { "should be empty" in { val stackActor = emptyStackActor val futureStackInfo = stackActor ? Size futureStackInfo map { stackInfo => assert(stackInfo.isEmpty) } }
"should complain on peek" in { recoverToSucceededIf[IllegalStateException] { emptyStackActor ? Peek } }
"should complain on pop" in { recoverToSucceededIf[IllegalStateException] { emptyStackActor ? Pop } } }
"(with one item)" - { "should" - { behave like nonEmptyStackActor(almostEmptyStackActor, LastValuePushed, almostEmptyStackActorName) behave like nonFullStackActor(almostEmptyStackActor, almostEmptyStackActorName) } }
"(with one item less than capacity)" - { "should" - { behave like nonEmptyStackActor(almostFullStackActor, LastValuePushed, almostFullStackActorName) behave like nonFullStackActor(almostFullStackActor, almostFullStackActorName) } }
"(full)" - {
"should be full" in { val stackActor = fullStackActor val futureStackInfo = stackActor ? Size futureStackInfo map { stackInfo => assert(stackInfo.isFull) } }
"should" - { behave like nonEmptyStackActor(fullStackActor, LastValuePushed, fullStackActorName) }
"should complain on a push" in { val stackActor = fullStackActor assertThrows[IllegalStateException] { stackActor ! Push(10) } } } } }
If you load these classes into the Scala interpreter (with scalatest's JAR file on the class path), and execute it, you'll see:
scala> org.scalatest.run(new StackSpec)
StackSpec:
A Stack
(when empty)
- should be empty
- should complain on peek
- should complain on pop
(with one item)
should
- return non-empty StackInfo when Size is fired at non-empty stack actor: almost empty stack actor
- return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: almost empty stack actor
- return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: almost empty stack actor
- return non-full StackInfo when Size is fired at non-full stack actor: almost empty stack actor
- return before and after StackInfo that has existing size + 1 and new item as top when Push is fired at non-full stack actor: almost empty stack actor
(with one item less than capacity)
should
- return non-empty StackInfo when Size is fired at non-empty stack actor: almost full stack actor
- return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: almost full stack actor
- return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: almost full stack actor
- return non-full StackInfo when Size is fired at non-full stack actor: almost full stack actor
- return before and after StackInfo that has existing size + 1 and new item as top when Push is fired at non-full stack actor: almost full stack actor
(full)
- should be full
should
- return non-empty StackInfo when Size is fired at non-empty stack actor: full stack actor
- return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: full stack actor
- return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: full stack actor
- should complain on a push
One thing to keep in mind when using shared tests is that in ScalaTest, each test in a suite must have a unique name.
If you register the same tests repeatedly in the same suite, one problem you may encounter is an exception at runtime
complaining that multiple tests are being registered with the same test name.
Although in an AsyncFreeSpec
, the -
clause is a nesting construct analogous to
AsyncFunSpec
's describe
clause, you many sometimes need to do a bit of
extra work to ensure that the test names are unique. If a duplicate test name problem shows up in an
AsyncFreeSpec
, you'll need to pass in a prefix or suffix string to add to each test name. You can call
toString
on the shared fixture object, or pass this string
the same way you pass any other data needed by the shared tests.
This is the approach taken by the previous AsyncFreeSpecStackBehaviors
example.
Given this AsyncFreeSpecStackBehaviors
trait, calling it with the almostEmptyStackActor
fixture, like this:
behave like nonEmptyStackActor(almostEmptyStackActor, LastValuePushed, almostEmptyStackActorName)
yields test names:
A Stack (when non-empty) should return non-empty StackInfo when Size is fired at non-empty stack actor: almost empty stack actor
A Stack (when non-empty) should return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: almost empty stack actor
A Stack (when non-empty) should return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: almost empty stack actor
Whereas calling it with the almostFullStackActor
fixture, like this:
behave like nonEmptyStackActor(almostFullStackActor, LastValuePushed, almostFullStackActorName)
yields different test names:
A Stack (when non-empty) should return non-empty StackInfo when Size is fired at non-empty stack actor: almost full stack actor
A Stack (when non-empty) should return before and after StackInfo that has existing size and lastItemAdded as top when Peek is fired at non-empty stack actor: almost full stack actor
A Stack (when non-empty) should return before and after StackInfo that has existing size - 1 and lastItemAdded as top when Pop is fired at non-empty stack actor: almost full stack actor
- Source
- AsyncFreeSpec.scala
- Alphabetic
- By Inheritance
- AsyncFreeSpec
- AsyncFreeSpecLike
- Documenting
- Alerting
- Notifying
- Informing
- AsyncTestRegistration
- AsyncTestSuite
- CompleteLastly
- RecoverMethods
- Suite
- Serializable
- Assertions
- TripleEquals
- TripleEqualsSupport
- AnyRef
- Any
- Hide All
- Show All
- Public
- Protected
Instance Constructors
- new AsyncFreeSpec()
Type Members
- trait NoArgAsyncTest extends () => FutureOutcome with TestData
A test function taking no arguments and returning a
FutureOutcome
.A test function taking no arguments and returning a
FutureOutcome
.For more detail and examples, see the relevant section in the documentation for trait
AsyncFlatSpec
.- Definition Classes
- AsyncTestSuite
- class ResultOfCompleteInvocation[T] extends AnyRef
Class that provides the
lastly
method of thecomplete
-lastly
syntax.Class that provides the
lastly
method of thecomplete
-lastly
syntax.- Definition Classes
- CompleteLastly
- class CheckingEqualizer[L] extends AnyRef
- Definition Classes
- TripleEqualsSupport
- class Equalizer[L] extends AnyRef
- Definition Classes
- TripleEqualsSupport
- final class FreeSpecStringWrapper extends AnyRef
A class that via an implicit conversion (named
convertToFreeSpecStringWrapper
) enables methodsin
,is
,taggedAs
andignore
, as well as the dash operator (-
), to be invoked onString
s.A class that via an implicit conversion (named
convertToFreeSpecStringWrapper
) enables methodsin
,is
,taggedAs
andignore
, as well as the dash operator (-
), to be invoked onString
s.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike
- final class ResultOfTaggedAsInvocationOnString extends AnyRef
Class that supports the registration of tagged tests.
Class that supports the registration of tagged tests.
Instances of this class are returned by the
taggedAs
method of classFreeSpecStringWrapper
.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike
Value Members
- final def !=(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def !==[T](right: Spread[T]): TripleEqualsInvocationOnSpread[T]
- Definition Classes
- TripleEqualsSupport
- def !==(right: Null): TripleEqualsInvocation[Null]
- Definition Classes
- TripleEqualsSupport
- def !==[T](right: T): TripleEqualsInvocation[T]
- Definition Classes
- TripleEqualsSupport
- final def ##: Int
- Definition Classes
- AnyRef → Any
- final def ==(arg0: Any): Boolean
- Definition Classes
- AnyRef → Any
- def ===[T](right: Spread[T]): TripleEqualsInvocationOnSpread[T]
- Definition Classes
- TripleEqualsSupport
- def ===(right: Null): TripleEqualsInvocation[Null]
- Definition Classes
- TripleEqualsSupport
- def ===[T](right: T): TripleEqualsInvocation[T]
- Definition Classes
- TripleEqualsSupport
- def alert: Alerter
Returns an
Alerter
that during test execution will forward strings passed to itsapply
method to the current reporter.Returns an
Alerter
that during test execution will forward strings passed to itsapply
method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked while thisAsyncFreeSpec
is being executed, such as from inside a test function, it will forward the information to the current reporter immediately. If invoked at any other time, it will print to the standard output. This method can be called safely by any thread.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → Alerting
- final def asInstanceOf[T0]: T0
- Definition Classes
- Any
- macro def assert(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: Position): Assertion
Assert that a boolean condition, described in
String
message
, is true.Assert that a boolean condition, described in
String
message
, is true. If the condition istrue
, this method returns normally. Else, it throwsTestFailedException
with a helpful error message appended with theString
obtained by invokingtoString
on the specifiedclue
as the exception's detail message.This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
- assert(a == b, "a good clue")
- assert(a != b, "a good clue")
- assert(a === b, "a good clue")
- assert(a !== b, "a good clue")
- assert(a > b, "a good clue")
- assert(a >= b, "a good clue")
- assert(a < b, "a good clue")
- assert(a <= b, "a good clue")
- assert(a startsWith "prefix", "a good clue")
- assert(a endsWith "postfix", "a good clue")
- assert(a contains "something", "a good clue")
- assert(a eq b, "a good clue")
- assert(a ne b, "a good clue")
- assert(a > 0 && b > 5, "a good clue")
- assert(a > 0 || b > 5, "a good clue")
- assert(a.isEmpty, "a good clue")
- assert(!a.isEmpty, "a good clue")
- assert(a.isInstanceOf[String], "a good clue")
- assert(a.length == 8, "a good clue")
- assert(a.size == 8, "a good clue")
- assert(a.exists(_ == 8), "a good clue")
At this time, any other form of expression will just get a
TestFailedException
with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the===
that returnsBoolean
to be the default in tests. This makes===
consistent between tests and production code.- condition
the boolean condition to assert
- clue
An objects whose
toString
method returns a message to include in a failure report.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
isnull
.TestFailedException
if the condition isfalse
.
- macro def assert(condition: Boolean)(implicit prettifier: Prettifier, pos: Position): Assertion
Assert that a boolean condition is true.
Assert that a boolean condition is true. If the condition is
true
, this method returns normally. Else, it throwsTestFailedException
.This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
- assert(a == b)
- assert(a != b)
- assert(a === b)
- assert(a !== b)
- assert(a > b)
- assert(a >= b)
- assert(a < b)
- assert(a <= b)
- assert(a startsWith "prefix")
- assert(a endsWith "postfix")
- assert(a contains "something")
- assert(a eq b)
- assert(a ne b)
- assert(a > 0 && b > 5)
- assert(a > 0 || b > 5)
- assert(a.isEmpty)
- assert(!a.isEmpty)
- assert(a.isInstanceOf[String])
- assert(a.length == 8)
- assert(a.size == 8)
- assert(a.exists(_ == 8))
At this time, any other form of expression will get a
TestFailedException
with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the===
that returnsBoolean
to be the default in tests. This makes===
consistent between tests and production code.- condition
the boolean condition to assert
- Definition Classes
- Assertions
- Exceptions thrown
TestFailedException
if the condition isfalse
.
- macro def assertCompiles(code: String)(implicit pos: Position): Assertion
Asserts that a given string snippet of code passes both the Scala parser and type checker.
Asserts that a given string snippet of code passes both the Scala parser and type checker.
You can use this to make sure a snippet of code compiles:
assertCompiles("val a: Int = 1")
Although
assertCompiles
is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string compiles, errors (i.e., snippets of code that do not compile) are reported as test failures at runtime.- code
the snippet of code that should compile
- Definition Classes
- Assertions
- macro def assertDoesNotCompile(code: String)(implicit pos: Position): Assertion
Asserts that a given string snippet of code does not pass either the Scala parser or type checker.
Asserts that a given string snippet of code does not pass either the Scala parser or type checker.
Often when creating libraries you may wish to ensure that certain arrangements of code that represent potential “user errors” do not compile, so that your library is more error resistant. ScalaTest's
Assertions
trait includes the following syntax for that purpose:assertDoesNotCompile("val a: String = \"a string")
Although
assertDoesNotCompile
is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string doesn't compile, errors (i.e., snippets of code that do compile) are reported as test failures at runtime.Note that the difference between
assertTypeError
andassertDoesNotCompile
is thatassertDoesNotCompile
will succeed if the given code does not compile for any reason, whereasassertTypeError
will only succeed if the given code does not compile because of a type error. If the given code does not compile because of a syntax error, for example,assertDoesNotCompile
will return normally butassertTypeError
will throw aTestFailedException
.- code
the snippet of code that should not type check
- Definition Classes
- Assertions
- def assertResult(expected: Any)(actual: Any)(implicit prettifier: Prettifier, pos: Position): Assertion
Assert that the value passed as
expected
equals the value passed asactual
.Assert that the value passed as
expected
equals the value passed asactual
. If theactual
value equals theexpected
value (as determined by==
),assertResult
returns normally. Else,assertResult
throws aTestFailedException
whose detail message includes the expected and actual values.- expected
the expected value
- actual
the actual value, which should equal the passed
expected
value
- Definition Classes
- Assertions
- Exceptions thrown
TestFailedException
if the passedactual
value does not equal the passedexpected
value.
- def assertResult(expected: Any, clue: Any)(actual: Any)(implicit prettifier: Prettifier, pos: Position): Assertion
Assert that the value passed as
expected
equals the value passed asactual
.Assert that the value passed as
expected
equals the value passed asactual
. If theactual
equals theexpected
(as determined by==
),assertResult
returns normally. Else, ifactual
is not equal toexpected
,assertResult
throws aTestFailedException
whose detail message includes the expected and actual values, as well as theString
obtained by invokingtoString
on the passedclue
.- expected
the expected value
- clue
An object whose
toString
method returns a message to include in a failure report.- actual
the actual value, which should equal the passed
expected
value
- Definition Classes
- Assertions
- Exceptions thrown
TestFailedException
if the passedactual
value does not equal the passedexpected
value.
- def assertThrows[T <: AnyRef](f: => Any)(implicit classTag: ClassTag[T], pos: Position): Assertion
Ensure that an expected exception is thrown by the passed function value.
Ensure that an expected exception is thrown by the passed function value. The thrown exception must be an instance of the type specified by the type parameter of this method. This method invokes the passed function. If the function throws an exception that's an instance of the specified type, this method returns
Succeeded
. Else, whether the passed function returns normally or completes abruptly with a different exception, this method throwsTestFailedException
.Note that the type specified as this method's type parameter may represent any subtype of
AnyRef
, not justThrowable
or one of its subclasses. In Scala, exceptions can be caught based on traits they implement, so it may at times make sense to specify a trait that the intercepted exception's class must mix in. If a class instance is passed for a type that could not possibly be used to catch an exception (such asString
, for example), this method will complete abruptly with aTestFailedException
.Also note that the difference between this method and
intercept
is that this method does not return the expected exception, so it does not let you perform further assertions on that exception. Instead, this method returnsSucceeded
, which means it can serve as the last statement in an async- or safe-style suite. It also indicates to the reader of the code that nothing further is expected about the thrown exception other than its type. The recommended usage is to useassertThrows
by default,intercept
only when you need to inspect the caught exception further.- f
the function value that should throw the expected exception
- classTag
an implicit
ClassTag
representing the type of the specified type parameter.- returns
the
Succeeded
singleton, if an exception of the expected type is thrown
- Definition Classes
- Assertions
- Exceptions thrown
TestFailedException
if the passed function does not complete abruptly with an exception that's an instance of the specified type.
- macro def assertTypeError(code: String)(implicit pos: Position): Assertion
Asserts that a given string snippet of code does not pass the Scala type checker, failing if the given snippet does not pass the Scala parser.
Asserts that a given string snippet of code does not pass the Scala type checker, failing if the given snippet does not pass the Scala parser.
Often when creating libraries you may wish to ensure that certain arrangements of code that represent potential “user errors” do not compile, so that your library is more error resistant. ScalaTest's
Assertions
trait includes the following syntax for that purpose:assertTypeError("val a: String = 1")
Although
assertTypeError
is implemented with a macro that determines at compile time whether the snippet of code represented by the passed string type checks, errors (i.e., snippets of code that do type check) are reported as test failures at runtime.Note that the difference between
assertTypeError
andassertDoesNotCompile
is thatassertDoesNotCompile
will succeed if the given code does not compile for any reason, whereasassertTypeError
will only succeed if the given code does not compile because of a type error. If the given code does not compile because of a syntax error, for example,assertDoesNotCompile
will return normally butassertTypeError
will throw aTestFailedException
.- code
the snippet of code that should not type check
- Definition Classes
- Assertions
- macro def assume(condition: Boolean, clue: Any)(implicit prettifier: Prettifier, pos: Position): Assertion
Assume that a boolean condition, described in
String
message
, is true.Assume that a boolean condition, described in
String
message
, is true. If the condition istrue
, this method returns normally. Else, it throwsTestCanceledException
with a helpful error message appended withString
obtained by invokingtoString
on the specifiedclue
as the exception's detail message.This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
- assume(a == b, "a good clue")
- assume(a != b, "a good clue")
- assume(a === b, "a good clue")
- assume(a !== b, "a good clue")
- assume(a > b, "a good clue")
- assume(a >= b, "a good clue")
- assume(a < b, "a good clue")
- assume(a <= b, "a good clue")
- assume(a startsWith "prefix", "a good clue")
- assume(a endsWith "postfix", "a good clue")
- assume(a contains "something", "a good clue")
- assume(a eq b, "a good clue")
- assume(a ne b, "a good clue")
- assume(a > 0 && b > 5, "a good clue")
- assume(a > 0 || b > 5, "a good clue")
- assume(a.isEmpty, "a good clue")
- assume(!a.isEmpty, "a good clue")
- assume(a.isInstanceOf[String], "a good clue")
- assume(a.length == 8, "a good clue")
- assume(a.size == 8, "a good clue")
- assume(a.exists(_ == 8), "a good clue")
At this time, any other form of expression will just get a
TestCanceledException
with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the===
that returnsBoolean
to be the default in tests. This makes===
consistent between tests and production code.- condition
the boolean condition to assume
- clue
An objects whose
toString
method returns a message to include in a failure report.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
isnull
.TestCanceledException
if the condition isfalse
.
- macro def assume(condition: Boolean)(implicit prettifier: Prettifier, pos: Position): Assertion
Assume that a boolean condition is true.
Assume that a boolean condition is true. If the condition is
true
, this method returns normally. Else, it throwsTestCanceledException
.This method is implemented in terms of a Scala macro that will generate a more helpful error message for expressions of this form:
- assume(a == b)
- assume(a != b)
- assume(a === b)
- assume(a !== b)
- assume(a > b)
- assume(a >= b)
- assume(a < b)
- assume(a <= b)
- assume(a startsWith "prefix")
- assume(a endsWith "postfix")
- assume(a contains "something")
- assume(a eq b)
- assume(a ne b)
- assume(a > 0 && b > 5)
- assume(a > 0 || b > 5)
- assume(a.isEmpty)
- assume(!a.isEmpty)
- assume(a.isInstanceOf[String])
- assume(a.length == 8)
- assume(a.size == 8)
- assume(a.exists(_ == 8))
At this time, any other form of expression will just get a
TestCanceledException
with message saying the given expression was false. In the future, we will enhance this macro to give helpful error messages in more situations. In ScalaTest 2.0, however, this behavior was sufficient to allow the===
that returnsBoolean
to be the default in tests. This makes===
consistent between tests and production code.- condition
the boolean condition to assume
- Definition Classes
- Assertions
- Exceptions thrown
TestCanceledException
if the condition isfalse
.
- val behave: BehaveWord
Supports shared test registration in
AsyncFreeSpec
s.Supports shared test registration in
AsyncFreeSpec
s.This field enables syntax such as the following:
behave like nonFullStack(stackWithOneItem) ^
For more information and examples of the use of <cod>behave, see the Shared tests section in the main documentation for this trait.
- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike
- def cancel(cause: Throwable)(implicit pos: Position): Nothing
Throws
TestCanceledException
, with the passedThrowable
cause, to indicate a test failed.Throws
TestCanceledException
, with the passedThrowable
cause, to indicate a test failed. ThegetMessage
method of the thrownTestCanceledException
will returncause.toString
.- cause
a
Throwable
that indicates the cause of the cancellation.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifcause
isnull
- def cancel(message: String, cause: Throwable)(implicit pos: Position): Nothing
Throws
TestCanceledException
, with the passedString
message
as the exception's detail message andThrowable
cause, to indicate a test failed.Throws
TestCanceledException
, with the passedString
message
as the exception's detail message andThrowable
cause, to indicate a test failed.- message
A message describing the failure.
- cause
A
Throwable
that indicates the cause of the failure.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
orcause
isnull
- def cancel(message: String)(implicit pos: Position): Nothing
Throws
TestCanceledException
, with the passedString
message
as the exception's detail message, to indicate a test was canceled.Throws
TestCanceledException
, with the passedString
message
as the exception's detail message, to indicate a test was canceled.- message
A message describing the cancellation.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
isnull
- def cancel()(implicit pos: Position): Nothing
Throws
TestCanceledException
to indicate a test was canceled.Throws
TestCanceledException
to indicate a test was canceled.- Definition Classes
- Assertions
- def clone(): AnyRef
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.CloneNotSupportedException]) @native()
- def complete[T](completeBlock: => T)(implicit futuristic: Futuristic[T]): ResultOfCompleteInvocation[T]
Registers a block of code that produces any "futuristic" type (any type
F
for which an implicitFuturistic[F]
instance is implicitly available), returning an object that offers alastly
method.Registers a block of code that produces any "futuristic" type (any type
F
for which an implicitFuturistic[F]
instance is implicitly available), returning an object that offers alastly
method.See the main documentation for trait
CompleteLastly
for more detail.- completeBlock
cleanup code to execute whether the code passed to
complete
throws an exception or succesfully returns a futuristic value.
- Definition Classes
- CompleteLastly
- implicit def convertAssertionToFutureAssertion(assertion: compatible.Assertion): Future[compatible.Assertion]
Implicitly converts an
Assertion
to aFuture[Assertion]
.Implicitly converts an
Assertion
to aFuture[Assertion]
.This implicit conversion is used to allow synchronous tests to be included along with asynchronous tests in an
AsyncTestSuite
. It will be- assertion
the
Assertion
to convert- returns
a
Future[Assertion]
that has already completed successfully (containing theSucceeded
singleton).
- Definition Classes
- AsyncTestSuite
- def convertEquivalenceToAToBConstraint[A, B](equivalenceOfB: Equivalence[B])(implicit ev: <:<[A, B]): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- def convertEquivalenceToBToAConstraint[A, B](equivalenceOfA: Equivalence[A])(implicit ev: <:<[B, A]): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- def convertToCheckingEqualizer[T](left: T): CheckingEqualizer[T]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- implicit def convertToEqualizer[T](left: T): Equalizer[T]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- implicit def convertToFreeSpecStringWrapper(s: String)(implicit pos: Position): FreeSpecStringWrapper
Implicitly converts
String
s toFreeSpecStringWrapper
, which enables methodsin
,is
,taggedAs
andignore
, as well as the dash operator (-
), to be invoked onString
s.Implicitly converts
String
s toFreeSpecStringWrapper
, which enables methodsin
,is
,taggedAs
andignore
, as well as the dash operator (-
), to be invoked onString
s.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike
- def defaultEquality[A]: Equality[A]
- Definition Classes
- TripleEqualsSupport
- final def eq(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def equals(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef → Any
- final def execute(testName: String = null, configMap: ConfigMap = ConfigMap.empty, color: Boolean = true, durations: Boolean = false, shortstacks: Boolean = false, fullstacks: Boolean = false, stats: Boolean = false): Unit
Executes one or more tests in this
Suite
, printing results to the standard output.Executes one or more tests in this
Suite
, printing results to the standard output.This method invokes
run
on itself, passing in values that can be configured via the parameters to this method, all of which have default values. This behavior is convenient when working with ScalaTest in the Scala interpreter. Here's a summary of this method's parameters and how you can use them:The
testName
parameterIf you leave
testName
at its default value (ofnull
), this method will passNone
to thetestName
parameter ofrun
, and as a result all the tests in this suite will be executed. If you specify atestName
, this method will passSome(testName)
torun
, and only that test will be run. Thus to run all tests in a suite from the Scala interpreter, you can write:scala> (new ExampleSuite).execute()
(The above syntax actually invokes the overloaded parameterless form of
execute
, which calls this form with its default parameter values.) To run just the test named"my favorite test"
in a suite from the Scala interpreter, you would write:scala> (new ExampleSuite).execute("my favorite test")
Or:
scala> (new ExampleSuite).execute(testName = "my favorite test")
The
configMap
parameterIf you provide a value for the
configMap
parameter, this method will pass it torun
. If not, the default value of an emptyMap
will be passed. For more information on how to use a config map to configure your test suites, see the config map section in the main documentation for this trait. Here's an example in which you configure a run with the name of an input file:scala> (new ExampleSuite).execute(configMap = Map("inputFileName" -> "in.txt")
The
color
parameterIf you leave the
color
parameter unspecified, this method will configure the reporter it passes torun
to print to the standard output in color (via ansi escape characters). If you don't want color output, specify false forcolor
, like this:scala> (new ExampleSuite).execute(color = false)
The
durations
parameterIf you leave the
durations
parameter unspecified, this method will configure the reporter it passes torun
to not print durations for tests and suites to the standard output. If you want durations printed, specify true fordurations
, like this:scala> (new ExampleSuite).execute(durations = true)
The
shortstacks
andfullstacks
parametersIf you leave both the
shortstacks
andfullstacks
parameters unspecified, this method will configure the reporter it passes torun
to not print stack traces for failed tests if it has a stack depth that identifies the offending line of test code. If you prefer a short stack trace (10 to 15 stack frames) to be printed with any test failure, specify true forshortstacks
:scala> (new ExampleSuite).execute(shortstacks = true)
For full stack traces, set
fullstacks
to true:scala> (new ExampleSuite).execute(fullstacks = true)
If you specify true for both
shortstacks
andfullstacks
, you'll get full stack traces.The
stats
parameterIf you leave the
stats
parameter unspecified, this method will not fireRunStarting
and eitherRunCompleted
orRunAborted
events to the reporter it passes torun
. If you specify true forstats
, this method will fire the run events to the reporter, and the reporter will print the expected test count before the run, and various statistics after, including the number of suites completed and number of tests that succeeded, failed, were ignored or marked pending. Here's how you get the stats:scala> (new ExampleSuite).execute(stats = true)
To summarize, this method will pass to
run
:testName
-None
if this method'stestName
parameter is left at its default value ofnull
, elseSome(testName)
.reporter
- a reporter that prints to the standard outputstopper
- aStopper
whoseapply
method always returnsfalse
filter
- aFilter
constructed withNone
fortagsToInclude
andSet()
fortagsToExclude
configMap
- theconfigMap
passed to this methoddistributor
-None
tracker
- a newTracker
Note: In ScalaTest, the terms "execute" and "run" basically mean the same thing and can be used interchangably. The reason this method isn't named
run
is that it takes advantage of default arguments, and you can't mix overloaded methods and default arguments in Scala. (If namedrun
, this method would have the same name but different arguments than the mainrun
method that takes seven arguments. Thus it would overload and couldn't be used with default argument values.)Design note: This method has two "features" that may seem unidiomatic. First, the default value of
testName
isnull
. Normally in Scala the type oftestName
would beOption[String]
and the default value would beNone
, as it is in this trait'srun
method. Thenull
value is used here for two reasons. First, in ScalaTest 1.5,execute
was changed from four overloaded methods to one method with default values, taking advantage of the default and named parameters feature introduced in Scala 2.8. To not break existing source code,testName
needed to have typeString
, as it did in two of the overloadedexecute
methods prior to 1.5. The other reason is thatexecute
has always been designed to be called primarily from an interpeter environment, such as the Scala REPL (Read-Evaluate-Print-Loop). In an interpreter environment, minimizing keystrokes is king. AString
type with anull
default value lets users typesuite.execute("my test name")
rather thansuite.execute(Some("my test name"))
, saving several keystrokes.The second non-idiomatic feature is that
shortstacks
andfullstacks
are all lower case rather than camel case. This is done to be consistent with theShell
, which also uses those forms. The reason lower case is used in theShell
is to save keystrokes in an interpreter environment. Most Unix commands, for example, are all lower case, making them easier and quicker to type. In the ScalaTestShell
, methods likeshortstacks
,fullstacks
, andnostats
, etc., are designed to be all lower case so they feel more like shell commands than methods.- testName
the name of one test to run.
- configMap
a
Map
of key-value pairs that can be used by the executingSuite
of tests.- color
a boolean that configures whether output is printed in color
- durations
a boolean that configures whether test and suite durations are printed to the standard output
- shortstacks
a boolean that configures whether short stack traces should be printed for test failures
- fullstacks
a boolean that configures whether full stack traces should be printed for test failures
- stats
a boolean that configures whether test and suite statistics are printed to the standard output
- Definition Classes
- Suite
- Exceptions thrown
IllegalArgumentException
iftestName
is defined, but no test with the specified test name exists in thisSuite
NullArgumentException
if the passedconfigMap
parameter isnull
.
- implicit def executionContext: ExecutionContext
- Definition Classes
- AsyncTestSuite
- def expectedTestCount(filter: Filter): Int
The total number of tests that are expected to run when this
Suite
'srun
method is invoked.The total number of tests that are expected to run when this
Suite
'srun
method is invoked.This trait's implementation of this method returns the sum of:
- the size of the
testNames
List
, minus the number of tests marked as ignored and any tests that are exluded by the passedFilter
- the sum of the values obtained by invoking
expectedTestCount
on every nestedSuite
contained innestedSuites
- filter
a
Filter
with which to filter tests to count based on their tags
- Definition Classes
- Suite
- the size of the
- def fail(cause: Throwable)(implicit pos: Position): Nothing
Throws
TestFailedException
, with the passedThrowable
cause, to indicate a test failed.Throws
TestFailedException
, with the passedThrowable
cause, to indicate a test failed. ThegetMessage
method of the thrownTestFailedException
will returncause.toString
.- cause
a
Throwable
that indicates the cause of the failure.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifcause
isnull
- def fail(message: String, cause: Throwable)(implicit pos: Position): Nothing
Throws
TestFailedException
, with the passedString
message
as the exception's detail message andThrowable
cause, to indicate a test failed.Throws
TestFailedException
, with the passedString
message
as the exception's detail message andThrowable
cause, to indicate a test failed.- message
A message describing the failure.
- cause
A
Throwable
that indicates the cause of the failure.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
orcause
isnull
- def fail(message: String)(implicit pos: Position): Nothing
Throws
TestFailedException
, with the passedString
message
as the exception's detail message, to indicate a test failed.Throws
TestFailedException
, with the passedString
message
as the exception's detail message, to indicate a test failed.- message
A message describing the failure.
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
ifmessage
isnull
- def fail()(implicit pos: Position): Nothing
Throws
TestFailedException
to indicate a test failed.Throws
TestFailedException
to indicate a test failed.- Definition Classes
- Assertions
- def finalize(): Unit
- Attributes
- protected[lang]
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.Throwable])
- final def getClass(): Class[_ <: AnyRef]
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
- def hashCode(): Int
- Definition Classes
- AnyRef → Any
- Annotations
- @native()
- def info: Informer
Returns an
Informer
that during test execution will forward strings passed to itsapply
method to the current reporter.Returns an
Informer
that during test execution will forward strings passed to itsapply
method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked from inside a scope, it will forward the information to the current reporter immediately. If invoked from inside a test function, it will record the information and forward it to the current reporter only after the test completed, asrecordedEvents
of the test completed event, such asTestSucceeded
. If invoked at any other time, it will print to the standard output. This method can be called safely by any thread.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → Informing
- def intercept[T <: AnyRef](f: => Any)(implicit classTag: ClassTag[T], pos: Position): T
Intercept and return an exception that's expected to be thrown by the passed function value.
Intercept and return an exception that's expected to be thrown by the passed function value. The thrown exception must be an instance of the type specified by the type parameter of this method. This method invokes the passed function. If the function throws an exception that's an instance of the specified type, this method returns that exception. Else, whether the passed function returns normally or completes abruptly with a different exception, this method throws
TestFailedException
.Note that the type specified as this method's type parameter may represent any subtype of
AnyRef
, not justThrowable
or one of its subclasses. In Scala, exceptions can be caught based on traits they implement, so it may at times make sense to specify a trait that the intercepted exception's class must mix in. If a class instance is passed for a type that could not possibly be used to catch an exception (such asString
, for example), this method will complete abruptly with aTestFailedException
.Also note that the difference between this method and
assertThrows
is that this method returns the expected exception, so it lets you perform further assertions on that exception. By contrast, theassertThrows
method returnsSucceeded
, which means it can serve as the last statement in an async- or safe-style suite.assertThrows
also indicates to the reader of the code that nothing further is expected about the thrown exception other than its type. The recommended usage is to useassertThrows
by default,intercept
only when you need to inspect the caught exception further.- f
the function value that should throw the expected exception
- classTag
an implicit
ClassTag
representing the type of the specified type parameter.- returns
the intercepted exception, if it is of the expected type
- Definition Classes
- Assertions
- Exceptions thrown
TestFailedException
if the passed function does not complete abruptly with an exception that's an instance of the specified type.
- final def isInstanceOf[T0]: Boolean
- Definition Classes
- Any
- def lowPriorityTypeCheckedConstraint[A, B](implicit equivalenceOfB: Equivalence[B], ev: <:<[A, B]): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- def markup: Documenter
Returns a
Documenter
that during test execution will forward strings passed to itsapply
method to the current reporter.Returns a
Documenter
that during test execution will forward strings passed to itsapply
method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked from inside a scope, it will forward the information to the current reporter immediately. If invoked from inside a test function, it will record the information and forward it to the current reporter only after the test completed, asrecordedEvents
of the test completed event, such asTestSucceeded
. If invoked at any other time, it will print to the standard output. This method can be called safely by any thread.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → Documenting
- final def ne(arg0: AnyRef): Boolean
- Definition Classes
- AnyRef
- def nestedSuites: IndexedSeq[Suite]
An immutable
IndexedSeq
of thisSuite
object's nestedSuite
s.An immutable
IndexedSeq
of thisSuite
object's nestedSuite
s. If thisSuite
contains no nestedSuite
s, this method returns an emptyIndexedSeq
. This trait's implementation of this method returns an emptyList
.- Definition Classes
- Suite
- def note: Notifier
Returns a
Notifier
that during test execution will forward strings passed to itsapply
method to the current reporter.Returns a
Notifier
that during test execution will forward strings passed to itsapply
method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked while thisAsyncFreeSpec
is being executed, such as from inside a test function, it will forward the information to the current reporter immediately. If invoked at any other time, it will print to the standard output. This method can be called safely by any thread.- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → Notifying
- final def notify(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- final def notifyAll(): Unit
- Definition Classes
- AnyRef
- Annotations
- @native()
- def parallelAsyncTestExecution: Boolean
- Attributes
- protected[scalatest]
- Definition Classes
- AsyncTestSuite
- def pending: Assertion with PendingStatement
Throws
TestPendingException
to indicate a test is pending.Throws
TestPendingException
to indicate a test is pending.A pending test is one that has been given a name but is not yet implemented. The purpose of pending tests is to facilitate a style of testing in which documentation of behavior is sketched out before tests are written to verify that behavior (and often, the before the behavior of the system being tested is itself implemented). Such sketches form a kind of specification of what tests and functionality to implement later.
To support this style of testing, a test can be given a name that specifies one bit of behavior required by the system being tested. The test can also include some code that sends more information about the behavior to the reporter when the tests run. At the end of the test, it can call method
pending
, which will cause it to complete abruptly withTestPendingException
. Because tests in ScalaTest can be designated as pending withTestPendingException
, both the test name and any information sent to the reporter when running the test can appear in the report of a test run. (In other words, the code of a pending test is executed just like any other test.) However, because the test completes abruptly withTestPendingException
, the test will be reported as pending, to indicate the actual test, and possibly the functionality it is intended to test, has not yet been implemented.Note: This method always completes abruptly with a
TestPendingException
. Thus it always has a side effect. Methods with side effects are usually invoked with parentheses, as inpending()
. This method is defined as a parameterless method, in flagrant contradiction to recommended Scala style, because it forms a kind of DSL for pending tests. It enables tests in suites such asFunSuite
orFunSpec
to be denoted by placing "(pending)
" after the test name, as in:test("that style rules are not laws") (pending)
Readers of the code see "pending" in parentheses, which looks like a little note attached to the test name to indicate it is pending. Whereas "
(pending())
looks more like a method call, "(pending)
" lets readers stay at a higher level, forgetting how it is implemented and just focusing on the intent of the programmer who wrote the code.- Definition Classes
- Assertions
- def pendingUntilFixed(f: => Unit)(implicit pos: Position): Assertion with PendingStatement
Execute the passed block of code, and if it completes abruptly, throw
TestPendingException
, else throwTestFailedException
.Execute the passed block of code, and if it completes abruptly, throw
TestPendingException
, else throwTestFailedException
.This method can be used to temporarily change a failing test into a pending test in such a way that it will automatically turn back into a failing test once the problem originally causing the test to fail has been fixed. At that point, you need only remove the
pendingUntilFixed
call. In other words, apendingUntilFixed
surrounding a block of code that isn't broken is treated as a test failure. The motivation for this behavior is to encourage people to removependingUntilFixed
calls when there are no longer needed.This method facilitates a style of testing in which tests are written before the code they test. Sometimes you may encounter a test failure that requires more functionality than you want to tackle without writing more tests. In this case you can mark the bit of test code causing the failure with
pendingUntilFixed
. You can then write more tests and functionality that eventually will get your production code to a point where the original test won't fail anymore. At this point the code block marked withpendingUntilFixed
will no longer throw an exception (because the problem has been fixed). This will in turn causependingUntilFixed
to throwTestFailedException
with a detail message explaining you need to go back and remove thependingUntilFixed
call as the problem orginally causing your test code to fail has been fixed.- f
a block of code, which if it completes abruptly, should trigger a
TestPendingException
- Definition Classes
- Assertions
- Exceptions thrown
TestPendingException
if the passed block of code completes abruptly with anException
orAssertionError
- def recoverToExceptionIf[T <: AnyRef](future: Future[Any])(implicit classTag: ClassTag[T], exCtx: ExecutionContext, pos: Position): Future[T]
Transforms a future of any type into a
Future[T]
, whereT
is a given expected exception type, which succeeds if the given future completes with aFailure
containing the specified exception type.Transforms a future of any type into a
Future[T]
, whereT
is a given expected exception type, which succeeds if the given future completes with aFailure
containing the specified exception type.See the main documentation for this trait for more detail and examples.
- future
A future of any type, which you expect to fail with an exception of the specified type T
- returns
a Future[T] containing on success the expected exception, or containing on failure a
TestFailedException
- Definition Classes
- RecoverMethods
- def recoverToSucceededIf[T <: AnyRef](future: Future[Any])(implicit classTag: ClassTag[T], exCtx: ExecutionContext, pos: Position): Future[compatible.Assertion]
Transforms a future of any type into a
Future[Assertion]
that succeeds if the future completes with aFailure
containing the specified exception type.Transforms a future of any type into a
Future[Assertion]
that succeeds if the future completes with aFailure
containing the specified exception type.See the main documentation for this trait for more detail and examples.
- future
A future of any type, which you expect to fail with an exception of the specified type T
- returns
a Future[Assertion] containing on success the
Succeeded
singleton, or containing on failure aTestFailedException
- Definition Classes
- RecoverMethods
- final def registerAsyncTest(testText: String, testTags: Tag*)(testFun: => Future[compatible.Assertion])(implicit pos: Position): Unit
Registers a test.
Registers a test.
- testText
the test text
- testTags
the test tags
- testFun
the test function
- Definition Classes
- AsyncFreeSpecLike → AsyncTestRegistration
- final def registerIgnoredAsyncTest(testText: String, testTags: Tag*)(testFun: => Future[compatible.Assertion])(implicit pos: Position): Unit
Registers an ignored test.
Registers an ignored test.
- testText
the test text
- testTags
the test tags
- testFun
the test function
- Definition Classes
- AsyncFreeSpecLike → AsyncTestRegistration
- def rerunner: Option[String]
The fully qualified class name of the rerunner to rerun this suite.
The fully qualified class name of the rerunner to rerun this suite. This implementation will look at this.getClass and see if it is either an accessible Suite, or it has a WrapWith annotation. If so, it returns the fully qualified class name wrapped in a Some, or else it returns None.
- Definition Classes
- Suite
- def run(testName: Option[String], args: Args): Status
Runs this suite of tests.
Runs this suite of tests.
If
testName
isNone
, this trait's implementation of this method calls these two methods on this object in this order:runNestedSuites
runTests
If
testName
is defined, then this trait's implementation of this method callsrunTests
, but does not callrunNestedSuites
. This behavior is part of the contract of this method. Subclasses that overriderun
must take care not to callrunNestedSuites
iftestName
is defined. (TheOneInstancePerTest
trait depends on this behavior, for example.)Subclasses and subtraits that override this
run
method can implement them without invoking either therunTests
orrunNestedSuites
methods, which are invoked by this trait's implementation of this method. It is recommended, but not required, that subclasses and subtraits that overriderun
in a way that does not invokerunNestedSuites
also overriderunNestedSuites
and make it final. Similarly it is recommended, but not required, that subclasses and subtraits that overriderun
in a way that does not invokerunTests
also overriderunTests
(andrunTest
, which this trait's implementation ofrunTests
calls) and make it final. The implementation of these final methods can either invoke the superclass implementation of the method, or throw anUnsupportedOperationException
if appropriate. The reason for this recommendation is that ScalaTest includes several traits that override these methods to allow behavior to be mixed into aSuite
. For example, traitBeforeAndAfterEach
overridesrunTests
s. In aSuite
subclass that no longer invokesrunTests
fromrun
, theBeforeAndAfterEach
trait is not applicable. Mixing it in would have no effect. By makingrunTests
final in such aSuite
subtrait, you make the attempt to mixBeforeAndAfterEach
into a subclass of your subtrait a compiler error. (It would fail to compile with a complaint thatBeforeAndAfterEach
is trying to overriderunTests
, which is a final method in your trait.)- testName
an optional name of one test to run. If
None
, all relevant tests should be run. I.e.,None
acts like a wildcard that means run all relevant tests in thisSuite
.- args
the
Args
for this run- returns
a
Status
object that indicates when all tests and nested suites started by this method have completed, and whether or not a failure occurred.
- Definition Classes
- AsyncFreeSpecLike → Suite
- Exceptions thrown
IllegalArgumentException
iftestName
is defined, but no test with the specified test name exists in thisSuite
NullArgumentException
if any passed parameter isnull
.
- def runNestedSuites(args: Args): Status
Run zero to many of this
Suite
's nestedSuite
s.Run zero to many of this
Suite
's nestedSuite
s.If the passed
distributor
isNone
, this trait's implementation of this method invokesrun
on each nestedSuite
in theList
obtained by invokingnestedSuites
. If a nestedSuite
'srun
method completes abruptly with an exception, this trait's implementation of this method reports that theSuite
aborted and attempts to run the next nestedSuite
. If the passeddistributor
is defined, this trait's implementation puts each nestedSuite
into theDistributor
contained in theSome
, in the order in which theSuite
s appear in theList
returned bynestedSuites
, passing in a newTracker
obtained by invokingnextTracker
on theTracker
passed to this method.Implementations of this method are responsible for ensuring
SuiteStarting
events are fired to theReporter
before executing any nestedSuite
, and eitherSuiteCompleted
orSuiteAborted
after executing any nestedSuite
.- args
the
Args
for this run- returns
a
Status
object that indicates when all nested suites started by this method have completed, and whether or not a failure occurred.
- Attributes
- protected
- Definition Classes
- Suite
- Exceptions thrown
NullArgumentException
if any passed parameter isnull
.
- def runTest(testName: String, args: Args): Status
Run a test.
Run a test. This trait's implementation runs the test registered with the name specified by
testName
. Each test's name is a concatenation of the text of all describers surrounding a test, from outside in, and the test's spec text, with one space placed between each item. (See the documentation fortestNames
for an example.)- testName
the name of one test to execute.
- args
the
Args
for this run- returns
a
Status
object that indicates when the test started by this method has completed, and whether or not it failed .
- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → AsyncTestSuite → Suite
- Exceptions thrown
NullArgumentException
if any oftestName
,reporter
,stopper
, orconfigMap
isnull
.
- def runTests(testName: Option[String], args: Args): Status
Run zero to many of this
AsyncFreeSpec
's tests.Run zero to many of this
AsyncFreeSpec
's tests.This method takes a
testName
parameter that optionally specifies a test to invoke. IftestName
isSome
, this trait's implementation of this method invokesrunTest
on this object, passing in:testName
- theString
value of thetestName
Option
passed to this methodreporter
- theReporter
passed to this method, or one that wraps and delegates to itstopper
- theStopper
passed to this method, or one that wraps and delegates to itconfigMap
- theconfigMap
passed to this method, or one that wraps and delegates to it
This method takes a
Set
of tag names that should be included (tagsToInclude
), and aSet
that should be excluded (tagsToExclude
), when deciding which of thisSuite
's tests to execute. IftagsToInclude
is empty, all tests will be executed except those those belonging to tags listed in thetagsToExclude
Set
. IftagsToInclude
is non-empty, only tests belonging to tags mentioned intagsToInclude
, and not mentioned intagsToExclude
will be executed. However, iftestName
isSome
,tagsToInclude
andtagsToExclude
are essentially ignored. Only iftestName
isNone
willtagsToInclude
andtagsToExclude
be consulted to determine which of the tests named in thetestNames
Set
should be run. For more information on trait tags, see the main documentation for this trait.If
testName
isNone
, this trait's implementation of this method invokestestNames
on thisSuite
to get aSet
of names of tests to potentially execute. (AtestNames
value ofNone
essentially acts as a wildcard that means all tests in thisSuite
that are selected bytagsToInclude
andtagsToExclude
should be executed.) For each test in thetestName
Set
, in the order they appear in the iterator obtained by invoking theelements
method on theSet
, this trait's implementation of this method checks whether the test should be run based on thetagsToInclude
andtagsToExclude
Set
s. If so, this implementation invokesrunTest
, passing in:testName
- theString
name of the test to run (which will be one of the names in thetestNames
Set
)reporter
- theReporter
passed to this method, or one that wraps and delegates to itstopper
- theStopper
passed to this method, or one that wraps and delegates to itconfigMap
- theconfigMap
passed to this method, or one that wraps and delegates to it
- testName
an optional name of one test to run. If
None
, all relevant tests should be run. I.e.,None
acts like a wildcard that means run all relevant tests in thisSuite
.- args
the
Args
for this run- returns
a
Status
object that indicates when all tests started by this method have completed, and whether or not a failure occurred.
- Attributes
- protected
- Definition Classes
- AsyncFreeSpecLike → Suite
- Exceptions thrown
IllegalArgumentException
iftestName
is defined, but no test with the specified test name exists in thisSuite
NullArgumentException
if any of the passed parameters isnull
.
- final val succeed: Assertion
The
Succeeded
singleton.The
Succeeded
singleton.You can use
succeed
to solve a type error when an async test does not end in eitherFuture[Assertion]
orAssertion
. BecauseAssertion
is a type alias forSucceeded.type
, puttingsucceed
at the end of a test body (or at the end of a function being used to map the final future of a test body) will solve the type error.- Definition Classes
- Assertions
- def suiteId: String
A string ID for this
Suite
that is intended to be unique among all suites reported during a run.A string ID for this
Suite
that is intended to be unique among all suites reported during a run.This trait's implementation of this method returns the fully qualified name of this object's class. Each suite reported during a run will commonly be an instance of a different
Suite
class, and in such cases, this default implementation of this method will suffice. However, in special cases you may need to override this method to ensure it is unique for each reported suite. For example, if you write aSuite
subclass that reads in a file whose name is passed to its constructor and dynamically creates a suite of tests based on the information in that file, you will likely need to override this method in yourSuite
subclass, perhaps by appending the pathname of the file to the fully qualified class name. That way if you run a suite of tests based on a directory full of these files, you'll have unique suite IDs for each reported suite.The suite ID is intended to be unique, because ScalaTest does not enforce that it is unique. If it is not unique, then you may not be able to uniquely identify a particular test of a particular suite. This ability is used, for example, to dynamically tag tests as having failed in the previous run when rerunning only failed tests.
- returns
this
Suite
object's ID.
- Definition Classes
- Suite
- def suiteName: String
A user-friendly suite name for this
Suite
.A user-friendly suite name for this
Suite
.This trait's implementation of this method returns the simple name of this object's class. This trait's implementation of
runNestedSuites
calls this method to obtain a name forReport
s to pass to thesuiteStarting
,suiteCompleted
, andsuiteAborted
methods of theReporter
.- returns
this
Suite
object's suite name.
- Definition Classes
- Suite
- final def synchronized[T0](arg0: => T0): T0
- Definition Classes
- AnyRef
- def tags: Map[String, Set[String]]
A
Map
whose keys areString
names of tagged tests and whose associated values are theSet
of tags for the test.A
Map
whose keys areString
names of tagged tests and whose associated values are theSet
of tags for the test. If thisAsyncFreeSpec
contains no tags, this method returns an emptyMap
.This trait's implementation returns tags that were passed as strings contained in
Tag
objects passed totaggedAs
.In addition, this trait's implementation will also auto-tag tests with class level annotations. For example, if you annotate
@Ignore
at the class level, all test methods in the class will be auto-annotated withorg.scalatest.Ignore
.- Definition Classes
- AsyncFreeSpecLike → Suite
- def testDataFor(testName: String, theConfigMap: ConfigMap = ConfigMap.empty): TestData
Provides a
TestData
instance for the passed test name, given the passed config map.Provides a
TestData
instance for the passed test name, given the passed config map.This method is used to obtain a
TestData
instance to pass towithFixture(NoArgTest)
andwithFixture(OneArgTest)
and thebeforeEach
andafterEach
methods of traitBeforeAndAfterEach
.- testName
the name of the test for which to return a
TestData
instance- theConfigMap
the config map to include in the returned
TestData
- returns
a
TestData
instance for the specified test, which includes the specified config map
- Definition Classes
- AsyncFreeSpecLike → Suite
- def testNames: Set[String]
An immutable
Set
of test names.An immutable
Set
of test names. If thisAsyncFreeSpec
contains no tests, this method returns an emptySet
.This trait's implementation of this method will return a set that contains the names of all registered tests. The set's iterator will return those names in the order in which the tests were registered. Each test's name is composed of the concatenation of the text of each surrounding describer, in order from outside in, and the text of the example itself, with all components separated by a space. For example, consider this
AsyncFreeSpec
:import org.scalatest.freespec.AsyncFreeSpec
class StackSpec extends AsyncFreeSpec { "A Stack" - { "when not empty" - { "must allow me to pop" in {} } "when not full" - { "must allow me to push" in {} } } }Invoking
testNames
on thisAsyncFreeSpec
will yield a set that contains the following two test name strings:"A Stack when not empty must allow me to pop" "A Stack when not full must allow me to push"
- Definition Classes
- AsyncFreeSpecLike → Suite
- def toString(): String
Returns a user friendly string for this suite, composed of the simple name of the class (possibly simplified further by removing dollar signs if added by the Scala interpeter) and, if this suite contains nested suites, the result of invoking
toString
on each of the nested suites, separated by commas and surrounded by parentheses.Returns a user friendly string for this suite, composed of the simple name of the class (possibly simplified further by removing dollar signs if added by the Scala interpeter) and, if this suite contains nested suites, the result of invoking
toString
on each of the nested suites, separated by commas and surrounded by parentheses.- returns
a user-friendly string for this suite
- Definition Classes
- AsyncFreeSpec → AnyRef → Any
- def typeCheckedConstraint[A, B](implicit equivalenceOfA: Equivalence[A], ev: <:<[B, A]): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- implicit def unconstrainedEquality[A, B](implicit equalityOfA: Equality[A]): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- final def wait(): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long, arg1: Int): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException])
- final def wait(arg0: Long): Unit
- Definition Classes
- AnyRef
- Annotations
- @throws(classOf[java.lang.InterruptedException]) @native()
- def withClue[T](clue: Any)(fun: => T): T
Executes the block of code passed as the second parameter, and, if it completes abruptly with a
ModifiableMessage
exception, prepends the "clue" string passed as the first parameter to the beginning of the detail message of that thrown exception, then rethrows it.Executes the block of code passed as the second parameter, and, if it completes abruptly with a
ModifiableMessage
exception, prepends the "clue" string passed as the first parameter to the beginning of the detail message of that thrown exception, then rethrows it. If clue does not end in a white space character, one space will be added between it and the existing detail message (unless the detail message is not defined).This method allows you to add more information about what went wrong that will be reported when a test fails. Here's an example:
withClue("(Employee's name was: " + employee.name + ")") { intercept[IllegalArgumentException] { employee.getTask(-1) } }
If an invocation of
intercept
completed abruptly with an exception, the resulting message would be something like:(Employee's name was Bob Jones) Expected IllegalArgumentException to be thrown, but no exception was thrown
- Definition Classes
- Assertions
- Exceptions thrown
NullArgumentException
if the passedclue
isnull
- def withFixture(test: NoArgAsyncTest): FutureOutcome
Run the passed test function in the context of a fixture established by this method.
Run the passed test function in the context of a fixture established by this method.
This method should set up the fixture needed by the tests of the current suite, invoke the test function, and if needed, register a callback on the resulting
FutureOutcome
to perform any clean up needed after the test completes. Because theNoArgAsyncTest
function passed to this method takes no parameters, preparing the fixture will require side effects, such as reassigning instancevar
s in thisSuite
or initializing a globally accessible external database. If you want to avoid reassigning instancevar
s you can use FixtureAsyncTestSuite.This trait's implementation of
runTest
invokes this method for each test, passing in aNoArgAsyncTest
whoseapply
method will execute the code of the test and returns its result.This trait's implementation of this method simply invokes the passed
NoArgAsyncTest
function.- test
the no-arg async test function to run with a fixture
- Definition Classes
- AsyncTestSuite
Deprecated Value Members
- def conversionCheckedConstraint[A, B](implicit equivalenceOfA: Equivalence[A], cnv: (B) => A): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- Annotations
- @deprecated
- Deprecated
(Since version 3.1.0) The conversionCheckedConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.
- def convertEquivalenceToAToBConversionConstraint[A, B](equivalenceOfB: Equivalence[B])(implicit ev: (A) => B): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- Annotations
- @deprecated
- Deprecated
(Since version 3.1.0) The convertEquivalenceToAToBConversionConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.
- def convertEquivalenceToBToAConversionConstraint[A, B](equivalenceOfA: Equivalence[A])(implicit ev: (B) => A): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- Annotations
- @deprecated
- Deprecated
(Since version 3.1.0) The convertEquivalenceToBToAConversionConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.
- def lowPriorityConversionCheckedConstraint[A, B](implicit equivalenceOfB: Equivalence[B], cnv: (A) => B): CanEqual[A, B]
- Definition Classes
- TripleEquals → TripleEqualsSupport
- Annotations
- @deprecated
- Deprecated
(Since version 3.1.0) The lowPriorityConversionCheckedConstraint method has been deprecated and will be removed in a future version of ScalaTest. It is no longer needed now that the deprecation period of ConversionCheckedTripleEquals has expired. It will not be replaced.
- final val styleName: String
The
styleName
lifecycle method has been deprecated and will be removed in a future version of ScalaTest.The
styleName
lifecycle method has been deprecated and will be removed in a future version of ScalaTest.This method was used to support the chosen styles feature, which was deactivated in 3.1.0. The internal modularization of ScalaTest in 3.2.0 will replace chosen styles as the tool to encourage consistency across a project. We do not plan a replacement for
styleName
.- Definition Classes
- AsyncFreeSpecLike → Suite
- Annotations
- @deprecated
- Deprecated
(Since version 3.1.0) The styleName lifecycle method has been deprecated and will be removed in a future version of ScalaTest with no replacement.