ScalaTest support in SuperSafe Community Edition

Artima SuperSafe is a commercial Scala compiler plugin with a free Community Edition that checks ScalaTest/Scalactic === and matcher expressions for correctness. Using SuperSafe Community Edition together with ScalaTest can save you time and ensure certain errors do not exist in your code. (See the installation section below for instructions on installing SuperSafe Community Edition.)

scala> import org.scalatest._
import org.scalatest._

scala> import Assertions._
import Assertions._

scala> val x = Some(1)
x: Some[Int] = Some(1)

scala> assert(x === 1)
<console>:18: error: [Artima SuperSafe] Values of type Some[Int] and Int may
not be compared with the === operator. If you really want to compare them for
equality, configure Artima SuperSafe to allow those types to be compared for
equality.  For more information on this kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       assert(x === 1)
             ^

scala> assert(x !== 1) // Note this assertion would have succeeded
<console>:18: error: [Artima SuperSafe] Values of type Some[Int] and Int may
not be compared with the !== operator. If you really want to compare them for
inequality, configure Artima SuperSafe to allow those types to be compared for
inequality (which will also enable them to be compared for equality).  For
more information on this kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       assert(x !== 1)
             ^

scala> import Matchers._
import Matchers._

scala> x should equal (1)
<console>:21: error: [Artima SuperSafe] Values of type Some[Int] and Int may
not be compared for equality with ScalaTest's equal matcher syntax. If you
really want this expression to compile, configure Artima SuperSafe to allow
Some[Int] and Int to be compared for equality.  For more information on this
kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       x should equal (1)
                       ^

scala> x should not equal 1 // Note this assertion would have succeeded
<console>:21: error: [Artima SuperSafe] Values of type Some[Int] and Int may
not be compared for equality with ScalaTest's not equal matcher syntax. If you
really want this expression to compile, configure Artima SuperSafe to allow
Some[Int] and Int to be compared for equality.  For more information on this
kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       x should not equal 1
                          ^

scala> x shouldBe "hi"
<console>:21: error: [Artima SuperSafe] Values of type Some[Int] and String
may not be compared for equality with ScalaTest's shouldBe matcher syntax. If
you really want this expression to compile, configure Artima SuperSafe to
allow Some[Int] and String to be compared for equality.  For more information
on this kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       x shouldBe "hi"
                  ^

scala> x should === ("hi")
<console>:21: error: [Artima SuperSafe] Values of type Some[Int] and String
may not be compared for equality with ScalaTest's === matcher syntax. If you
really want this expression to compile, configure Artima SuperSafe to allow
Some[Int] and String to be compared for equality.  For more information on
this kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       x should === ("hi")
                     ^

scala> List(1, 2, 3) should contain ("hi")
<console>:20: error: [Artima SuperSafe] Values of type Int and String may not
be compared for equality with ScalaTest's contain matcher syntax. If you
really want this expression to compile, configure Artima SuperSafe to allow
Int and String to be compared for equality.  For more information on this
kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       List(1, 2, 3) should contain ("hi")
                                     ^

scala> List(1, 2, 3) should not contain ("ho")
<console>:20: error: [Artima SuperSafe] Values of type Int and String may not
be compared for equality with ScalaTest's contain matcher syntax. If you
really want this expression to compile, configure Artima SuperSafe to allow
Int and String to be compared for equality.  For more information on this
kind of error, see:
http://www.artima.com/supersafe_user_guide.html#safer-equality
       List(1, 2, 3) should not contain ("ho")
                                         ^

scala> List(1, 2, 3) should contain oneOf ("hi", "ho")
:20: error: [Artima SuperSafe] Values of type List[Int] and String may not be
compared for equality with ScalaTest's oneOf matcher syntax. If you really
want this expression to compile, configure Artima SuperSafe to allow Int and
wtring to be compared for equality.  For more information on this kind of
error, see: http://www.artima.com/supersafe_user_guide.html#safer-equality
       List(1, 2, 3) should contain oneOf ("hi", "ho")
                                           ^

Installation of SuperSafe Community Edition

If you are using sbt as your build tool, you can install the SuperSafe Community Edition in two easy steps.

1. Add the Artima Maven Repository as a resolver in ~/.sbt/0.13/global.sbt, like this:

resolvers += "Artima Maven Repository" at "http://repo.artima.com/releases"

2. Add the following line to your project/plugins.sbt:

addSbtPlugin("com.artima.supersafe" % "sbtplugin" % "1.1.12")

Note: If using ScalaTest 2.2.6 or earlier, use SuperSafe version 1.1.0-RC6 instead, which will be the last version of SuperSafe to support ScalaTest 2.x.

If you are using Maven as your build tool, you can install the community edition of SuperSafe by adding the compiler plugin to your pom.xml, like this:

<plugin>
    <groupId>net.alchim31.maven</groupId>
    <artifactId>scala-maven-plugin</artifactId>
    <configuration>
        <compilerPlugins>
            <compilerPlugin>
                <groupId>com.artima.supersafe</groupId>
                <artifactId>supersafe_2.13.14</artifactId>
                <version>1.1.12</version>
            </compilerPlugin>
        </compilerPlugins>
    </configuration>
    <executions>
        ...
    </executions>
</plugin>

Note: If using ScalaTest 2.2.6 or earlier, use SuperSafe version 1.1.0-RC6 instead, which will be the last version of SuperSafe to support ScalaTest 2.x.

Note: You need to use the exact Scala version in the artifactId, because compiler plugin depends on compiler API that's not binary compatible between Scala minor releases.