How do I Dynamically create a Test Suite in JUnit 4?

Question

I would like to create a junit test suite using JUnit 4 where the names of the test classes to be included are not known until the test suite is run.

In JUnit 3 I could do this:

public final class MasterTester extends TestCase
{
  /**
   * Used by junit to specify what TestCases to run.
   * 
   * @return a suite containing what TestCases to run
   */
  public static TestSuite suite() {
    TestSuite suite = new TestSuite();

    for(Class<?> klass : gatherTestClasses()) {
      suite.addTestSuite(klass);
    }

    return suite;
  }
}

and let the gatherTestClasses() method deal with figuring out what test classes to run.

In JUnit 4, the documentation says to use an annotation: @SuiteClasses({TestClass1.class, TestClass2.class...}) to build up my test suite. There are numerous SO answers showing how to do this. Unfortunately the examples I see do not seem to allow for passing a dynamically generated list of TestClasses.

This SO answer suggested I would have to subclass BlockJUnit4ClassRunner which I do not want to do.

Dynamically specified test suites seem like something that must be in JUnit 4 somewhere. Does anyone know where?

Answer 1

I found Classpath suite quite useful when used with a naming convention on my test classes.

https://github.com/takari/takari-cpsuite

Here is an example:

import org.junit.extensions.cpsuite.ClasspathSuite;
import org.junit.runner.RunWith;

@RunWith(ClasspathSuite.class)
@ClassnameFilters({".*UnitTest"})
public class MySuite {
}