JUnit 4 Scala

Having just tried the very basics of getting ScalaIDE up and running for Scala I naturally immediately want unit tests because like any good Java developer I believe my code doesn't work until proven otherwise.

The internets turned up a number of fairly ugly sounding solutions for getting unit testing going in Scala so I thought rather than try that, why not just see if I can use ye olde JUnit "just like Java" (does that make me a bad Scala user?). Scala compiles to normal .class files so provided I get both Scala and JUnit on classpath it should work just fine. And it does!

First I expressed my dependence on JUnit. As I'm using a simple Eclipse test project I just right-clicked the project, selected Build Path>Add Libraries, picked JUnit and then selected to use JUnit 4. This added the JUnit 4 entry to my .classpath for me:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
 <classpathentry kind="src" path="src"/>
 <classpathentry kind="con" path="org.scala-ide.sdt.launching.SCALA_CONTAINER"/>
 <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6"/>
 <classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/4"/>
 <classpathentry kind="output" path="bin"/>
</classpath>

Next I created a test class, imported the bits of JUnit I needed, slapped @Test onto a few methods, held my breath, and hit Alt+Shift+X, T to run as JUnit test. And like magic it worked perfectly!

The code:

import org.junit.Assert._
import org.junit.Test

class FizzBuzzTestCase {
    @Test
    def meFail() = assertEquals(1, 2) 
 
    @Test
    def meSucceed() = assertEquals(1, 1)
}

The outcome:

Hooray! Super simple, familiar, and effective :)