[FIXED] Java Junit4 Supporting extended base class

Issue

a question:

When I do something like:

package path.to.common.package.test;
@BeforeClass
public class CommonTestSetup {

  public void setUp() {
   // Setup Stiff
  }
}

And the other class setup in the same package:

package path.to.common.package.test;
public class TestTest extends CommonTestSetup {
    @Test
    public void testGetTestReturnsCorrectStrings() {
    // do asserts etc
    }
}

And then executing JUnit test on testGetTestReturnsCorrectStrings I am getting an error:

org.junit.runners.model.InvalidTestClassError: Invalid test class 'org.junit.runner.manipulation.Filter':
  1. No runnable methods
    at org.junit.runners.ParentRunner.validate(ParentRunner.java:456)
    at org.junit.runners.ParentRunner.<init>(ParentRunner.java:99)
    at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:84)
    at org.junit.runners.JUnit4.<init>(JUnit4.java:23)
    at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:66)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:37)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:66)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:39)
    at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:36)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createFilteredTest(JUnit4TestLoader.java:80)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.createTest(JUnit4TestLoader.java:71)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestLoader.loadTests(JUnit4TestLoader.java:46)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:523)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:761)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:461)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:207)

Why is that? Does it mean JUnit 4 does not support Test classes extending a base class?

The idea behind this was to create a single SetUp base class, shared by many other test classes that need it. Originally I even tried to have the base class in another package entirely, then moved it to the same package for testing, and got a different error (the one above).

Solution

Based on the JUnit documentation:

Annotating a public static void no-arg method with @BeforeClass causes it to be run once before any of the test methods in the class

So move the @BeforeClass annotation to the setUp method and make into a static method.

Answered By - helospark
Answer Checked By - Marilyn (JavaFixing Volunteer)