ScalaTest

import org.scalatest.FlatSpec
import org.scalatest.matchers.ShouldMatchers

class StackSpec extends FlatSpec with ShouldMatchers {

  "A Stack" should "pop values in last-in-first-out order" in {
    val stack = new Stack[Int]
    stack.push(1)
    stack.push(2)
    stack.pop() should equal (2)
    stack.pop() should equal (1)
  }

  it should "throw NoSuchElementException if an empty stack is popped" in {
    val emptyStack = new Stack[String]
    evaluating { emptyStack.pop() } should produce [NoSuchElementException]
  }
}

With ScalaTest, you can test either Scala or Java code. By integrating with popular tools such as JUnit, TestNG, Ant, and Maven, ScalaTest makes it easy to take your testing to a higher, more productive level in new or existing Scala or Java projects.

Like the Scala language on which it is built, ScalaTest is designed to grow with the demands of its users: You can easily extend and compose ScalaTest's core components to address just about any special requirements you may have. As a result, ScalaTest can scale to projects of all sizes, from an individual exploring a new idea to large teams collaborating on mission-critical software.

One way ScalaTest scales down is that despite its rich feature set, ScalaTest is easy to get into. Building on what you already know from experience with other test frameworks, you can become productive with ScalaTest in about ten minutes.

To maximize your productivity, ScalaTest uses its own extension points to support several styles of testing out of the box. You can select and mix together whatever traits best fit your needs. For instance, the above example uses traits FlatSpec and ShouldMatchers to select a Behavior-Driven Development (BDD) style. When you run it, you get an informal specification of the software being tested:

$ scala -cp scalatest.jar org.scalatest.tools.Runner -p . -o -s StackSpec
Run starting. Expected test count is: 2
StackSpec:
A Stack 
- should pop values in last-in-first-out order
- should throw NoSuchElementException if an empty stack is popped
Run completed in 96 milliseconds.
Total number of tests run: 2
Suites: completed 1, aborted 0
Tests: succeeded 2, failed 0, ignored 0, pending 0
All tests passed.

Not into BDD? Not a problem. ScalaTest has many other traits to choose from. If you want to continue writing tests with JUnit or TestNG, but write them in Scala, ScalaTest has traits for that. If you prefer functional to unit testing, or need to do integration or acceptance testing, ScalaTest has traits for that. And much more. In short, ScalaTest is highly customizable, providing many extension points that let you design the testing experience you want even if none of its built-in traits exactly fit your needs.

Why not give it a try? Just Download ScalaTest, then visit the Quick Start page.