Toni Cebrián

BE AWARE!!! This post refers to an old SBT version, check the new one

Recently I have started a project that will be coded in Scala. Here I leave some instructions for setting up the the scala project that uses sbt for project management and creates unit tests with scalatests. This entry follows the structure of this post but introduces some changes and improvements.

1. Install sbt
2. Create a new project

   $ mkdir test-project
   $ cd test-project/
   $ sbt
   Project does not exist, create new project? (y/N/s) y
   Name: TestProject
   Organization: com.example
   Version [1.0]:
   Scala version [2.7.7]: 2.9.0
   sbt version [0.7.4]: 0.7.7
   

3. First we need to install a sbt plugin that collects test results and creates a xUnit report for using in a Continuous Integration Server like Jenkins. Details of that plugin can be found here. Create the file project/plugins/TestProjectPlugins.scala that instructs sbt to download the junit_xml_listener plugin.

   import sbt._
   
   class TestProjectPlugins(info: ProjectInfo) extends PluginDefinition(info) {
       val repo = "Christoph's Maven Repo" at "http://maven.henkelmann.eu/"
       val junitXml = "eu.henkelmann" % "junit_xml_listener" % "0.2"
   }
   

4. Once we have the configuration for getting the plugin, create the project dependencies and include the new listener into the available ones by overriding the defaults. So, create a build configuration file in project/build/TestProject.scala like:

   import sbt._
   import eu.henkelmann.sbt.JUnitXmlTestsListener
   
   class TestProject(info: ProjectInfo) extends DefaultProject(info) {
      val scalatest = "org.scalatest" %% "scalatest" % "1.6.1" % "test"
   
      //create a listener that writes to the normal output directory
      def junitXmlListener: TestReportListener = new JUnitXmlTestsListener(outputPath.toString)
      //add the new listener to the already configured ones
      override def testListeners: Seq[TestReportListener] = super.testListeners ++ Seq(junitXmlListener)
   }
   

5. Now, we have the project setup in place. Let’s write some classes and tests in order to check that everything is OK. First create the class under test in src/main/scala/Calc.scala

   package com.example
   
   object Calc {
       def add(x:Int, y:Int) : Int = x + y
   }
   

6. Now, create a test in src/test/scala/CaltTest.scala that assures that the class is working as expected

   package com.example.test
   
   import com.example.Calc
   import org.scalatest.Suite
   
   class CalcTest extends Suite {
   
       def testAddition() {
           assert(4 === Calc.add(2,2))
       }
   }
   

7. Now just test that tests pass by doing

   sbt clean-plugins
   sbt clean
   sbt update
   sbt test
   

   you should see something like this:

   $ sbt test
   [info] Building project test 1.0 against Scala 2.9.0
   [info]    using TestProject with sbt 0.7.7 and Scala 2.7.7
   [info]
   [info] == compile ==
   [info]   Source analysis: 0 new/modified, 0 indirectly invalidated, 0 removed.
   [info] Compiling main sources...
   [info] Nothing to compile.
   [info]   Post-analysis: 3 classes.
   [info] == compile ==
   [info]
   [info] == test-compile ==
   [info]   Source analysis: 0 new/modified, 0 indirectly invalidated, 0 removed.
   [info] Compiling test sources...
   [info] Nothing to compile.
   [info]   Post-analysis: 1 classes.
   [info] == test-compile ==
   [info]
   [info] == copy-test-resources ==
   [info] == copy-test-resources ==
   [info]
   [info] == copy-resources ==
   [info] == copy-resources ==
   [info]
   [info] == test-start ==
   [info] == test-start ==
   [info]
   [info] == com.example.test.CalcTest ==
   [info] CalcTest:
   [info] - testAddition
   [info] - testAdditionWithJavaObject
   [info] == com.example.test.CalcTest ==
   [info]
   [info] == test-complete ==
   [info] == test-complete ==
   [info]
   [info] == Test cleanup 1 ==
   [info] Deleting directory /tmp/sbt_b7e36ab4
   [info] == Test cleanup 1 ==
   [info]
   [info] == test-finish ==
   [info] Passed: : Total 2, Failed 0, Errors 0, Passed 2, Skipped 0
   [info]
   [info] All tests PASSED.
   [info] == test-finish ==
   [info]
   [info] == test-cleanup ==
   [info] == test-cleanup ==
   [info]
   [info] == test ==
   [info] == test ==
   [success] Successful.
   [info]
   [info] Total time: 1 s, completed 24-ago-2011 15:40:26
   [info]
   [info] Total session time: 2 s, completed 24-ago-2011 15:40:26
   [success] Build completed successfully.
   

The test reports are located in target/scala_*/test-reports/*.xml. I have setup a Mercurial project with all this code for fast start up, check it out here.