Getting started with Scala, Scalatest, and Maven

Question

I created a new scala project with the following:

mvn org.apache.maven.plugins:maven-archetype-plugin:2.2:generate 
    -DarchetypeGroupId=org.scala-tools.archetypes 
    -DarchetypeArtifactId=scala-archetype-simple 
    -DarchetypeVersion=1.3 
    -DgroupId=myGroup 
    -DartifactId=myProject
    -Dversion=0.1.0 
    -DinteractiveMode=false

Which gives me the following POM:

 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <groupId>myGroup</groupId>
   <artifactId>myProject</artifactId>
   <version>0.1.0</version>
   <name>${project.artifactId}</name>
   <description>My wonderfull scala app</description>
   <inceptionYear>2010</inceptionYear>
   <licenses>
     <license>
       <name>My License</name>
       <url>http://....</url>
       <distribution>repo</distribution>
     </license>
   </licenses>

   <properties>
     <maven.compiler.source>1.5</maven.compiler.source>
     <maven.compiler.target>1.5</maven.compiler.target>
     <encoding>UTF-8</encoding>
     <scala.version>2.8.0</scala.version>
   </properties>

 <!--
   <repositories>
     <repository>
       <id>scala-tools.org</id>
       <name>Scala-Tools Maven2 Repository</name>
       <url>http://scala-tools.org/repo-releases</url>
     </repository>
   </repositories>

   <pluginRepositories>
     <pluginRepository>
       <id>scala-tools.org</id>
       <name>Scala-Tools Maven2 Repository</name>
       <url>http://scala-tools.org/repo-releases</url>
     </pluginRepository>
   </pluginRepositories>
 -->
   <dependencies>
     <dependency>
       <groupId>org.scala-lang</groupId>
       <artifactId>scala-library</artifactId>
       <version>${scala.version}</version>
     </dependency>

     <!-- Test -->
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
       <version>4.8.1</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>org.scala-tools.testing</groupId>
       <artifactId>specs_${scala.version}</artifactId>
       <version>1.6.5</version>
       <scope>test</scope>
     </dependency>
     <dependency>
       <groupId>org.scalatest</groupId>
       <artifactId>scalatest</artifactId>
       <version>1.2</version>
       <scope>test</scope>
     </dependency>
   </dependencies>

   <build>
     <sourceDirectory>src/main/scala</sourceDirectory>
     <testSourceDirectory>src/test/scala</testSourceDirectory>
     <plugins>
       <plugin>
         <groupId>org.scala-tools</groupId>
         <artifactId>maven-scala-plugin</artifactId>
         <version>2.15.0</version>
         <executions>
           <execution>
             <goals>
               <goal>compile</goal>
               <goal>testCompile</goal>
             </goals>
             <configuration>
               <args>
                 <arg>-make:transitive</arg>
                 <arg>-dependencyfile</arg>
                 <arg>${project.build.directory}/.scala_dependencies</arg>
               </args>
             </configuration>
           </execution>
         </executions>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <version>2.6</version>
         <configuration>
           <useFile>false</useFile>
           <disableXmlReport>true</disableXmlReport>
           <!-- If you have classpath issue like NoDefClassError,... -->
           <!-- useManifestOnlyJar>false</useManifestOnlyJar -->
           <includes>
             <include>**/*Test.*</include>
             <include>**/*Suite.*</include>
           </includes>
         </configuration>
       </plugin>
     </plugins>
   </build>
 </project>

I can run mvn test and the sample tests run successfully. I'd like to use the most recent version of scala (I downloaded / installed 2.9.2...), but the most recent version of the org.scala-tools.testing scala_VERSION dependency seems to be 2.9.1. I made the following changes in my POM:

    <scala.version>2.9.1</scala.version>

and

    <dependency>
       <groupId>org.scala-tools.testing</groupId>
       <artifactId>specs_${scala.version}</artifactId>
       <version>1.6.5</version>
       <scope>test</scope>
    </dependency>

Now, running mvn test gives

 -------------------------------------------------------
  T E S T S
 -------------------------------------------------------
 Running samples.ListSuite
 Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.674 sec <<< FAILURE!
 initializationError(samples.ListSuite)  Time elapsed: 0.003 sec  <<< ERROR!
 java.lang.ClassCastException: scala.collection.immutable.Set$EmptySet$ cannot be
  cast to scala.collection.generic.Addable
         at org.scalatest.FunSuite$class.test(FunSuite.scala:1039)
         at samples.ListSuite.test(scalatest.scala:59)
         at samples.ListSuite.<init>(scalatest.scala:61)
         at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

         at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
         at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
         at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
         at java.lang.Class.newInstance0(Class.java:372)
         at java.lang.Class.newInstance(Class.java:325)
         at org.scalatest.junit.JUnitRunner.<init>(JUnitRunner.scala:62)
         at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

         at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
         at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
         at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
         at org.junit.internal.builders.AnnotatedBuilder.buildRunner(AnnotatedBuilder.java:31)
         at org.junit.internal.builders.AnnotatedBuilder.runnerForClass(AnnotatedBuilder.java:24)
         at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
         at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:29)
         at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:57)
         at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:24)
         at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:51)
         at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:120)
         at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:103)
         at org.apache.maven.surefire.Surefire.run(Surefire.java:169)
         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
         at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
         at java.lang.reflect.Method.invoke(Method.java:601)
         at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:350)
         at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1021)

 Running samples.StackSuite
 Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.12 sec
 Running samples.AppTest
 Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec

 Results :

 Tests in error:
   initializationError(samples.ListSuite)

 Tests run: 4, Failures: 0, Errors: 1, Skipped: 0

 [INFO] ------------------------------------------------------------------------
 [INFO] BUILD FAILURE
 [INFO] ------------------------------------------------------------------------
 [INFO] Total time: 6.880s
 [INFO] Finished at: Wed Oct 10 01:10:56 ADT 2012
 [INFO] Final Memory: 9M/112M
 [INFO] ------------------------------------------------------------------------
 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.6:test (default-test) on project myProject: There are test failures.
 [ERROR]
 [ERROR] Please refer to C:\Dropbox\work\dev\scalasandbox\target\surefire-reports for the individual test results.
 [ERROR] -> [Help 1]
 [ERROR]
 [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
 [ERROR] Re-run Maven using the -X switch to enable full debug logging.
 [ERROR]
 [ERROR] For more information about the errors and possible solutions, please read the following articles:
 [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

I presumably have some of the most simple tests possible (samples created by the maven archetype plugin), and bumping scala by a single minor version is breaking them? Should I just stick with scala 2.8 until the maven tools catch up?

Did you clean before running the tests? It looks like a binary incompatibility. — Iulian Dragos, Oct 10 '12 at 05:52

Nikita Volkov · Accepted Answer · 2013-04-28T08:20:47.367

16

Your artifact is outdated.

The latest version of Scala is 2.10. Currently ScalaTest is being distributed under different groupid and it supports the latest version of Scala. Here's the dependecy:

<dependency>
  <groupId>org.scalatest</groupId>
  <artifactId>scalatest_2.10</artifactId>
  <version>2.0.M5b</version>
  <scope>test</scope>
</dependency>

You will also require a different plugin:

  <plugin>
    <groupId>net.alchim31.maven</groupId>
    <artifactId>scala-maven-plugin</artifactId>
    <version>3.1.0</version>
    <executions>
      <execution>
        <phase>compile</phase>
        <goals>
          <goal>compile</goal>
          <goal>testCompile</goal>
        </goals>
      </execution>
    </executions>
  </plugin>

You don't need to specify any repositories, since all those artifacts are being distributed with the central repo.

Here's an example of a complete pom of a project depending on the Scala 2.10.

edited Apr 28 '13 at 08:20

answered Oct 10 '12 at 07:08

Nikita Volkov

42,792
11
94
169

The tests generated by the maven-archetype-plugin won't `mvn compile` with 2.10.0-M7. I guess the answer is "Don't use maven-archetype-plugin". Scala (tools/libs) seems to have a general lack of backwards-compatibility, which I find discouraging. – MrDrews Oct 10 '12 at 14:46
Right. Nobody uses the archetype. Frankly I find archetype generation a redundant and confusing feature of Maven. – Nikita Volkov Oct 10 '12 at 15:07
I cloned your sorm project, but it wouldn't compile (I'm missing your sext dependency). I think I will just stick with 2.8 for now -- I'm working through the Programming in Scala book which was written for 2.8, anyway. – MrDrews Oct 10 '12 at 15:08
Just get rid of the dependencies you don't need. For copy-pasting [this pom](https://github.com/nikita-volkov/sext/blob/develop/pom.xml) will suit you better. Don't use 2.8, it's too old. – Nikita Volkov Oct 10 '12 at 15:11
Yeah, I was just trying to get the simplest possible scala project compiling and testing through maven. I can `mvn test` your sext project with success, so I'll use that as my starting point. Thanks! – MrDrews Oct 10 '12 at 15:19

Andrzej Jozwik · Answer 2 · 2016-09-21T06:35:13.300

3

Use specs_2.9.1:1.6.9

And latest version of plugin

<groupId>net.alchim31.maven</groupId>
<artifactId>scala-maven-plugin</artifactId>
<version>3.2.2</version>

Old scala maven plugin in not longer supported.

edited Sep 21 '16 at 06:35

answered Oct 10 '12 at 07:12

Andrzej Jozwik

14,331
3
59
68

Thanks, but I'm getting the same ClassCastException with the new scala-maven-plugin. At least I can `mvn compile` without errors, though :S – MrDrews Oct 10 '12 at 14:41

Getting started with Scala, Scalatest, and Maven

2 Answers2