title: JUnit 5 (Jupiter) Testcases in eclipse projects not being run
body: <p>I have an eclipse workspace (version 2019-12, non-maven) with multiple web projects, all containing java code, and some referencing each other. At the end of the reference 'graph' is a project dedicated to contain a test suite, which in turn is supposed to reference all other projects' tests.
  All projects export their test-source folders. (All test classes are visible to the downstream projects).</p>
  
  <p>I started to define the following suite:</p>
  
  <pre class="lang-java prettyprint-override"><code>package platformTest;
  
  import org.junit.platform.runner.JUnitPlatform;
  import org.junit.platform.suite.api.SelectClasses;
  import org.junit.runner.RunWith;
  
  import de.***.PlatformEnvironmentTestcases;
  import de.***.ClientTestcases;
  
  @RunWith(JUnitPlatform.class)
  @SelectClasses({
      PlatformEnvironmentTestcases.class,
      ClientTestcases.class
  }) 
  public class JUnit5TestSuite {
      // test suite
  }
  </code></pre>
  
  <p>However the referenced test classes (though successfully running on their own, and being directly referenced) are not being executed at all.</p>
  
  <p>I tried:</p>
  
  <ul>
  <li>setting the debug config to junit4, with the result that no tests are executed. It seems the compatibility layer between junit 4 and 5 is not working here.</li>
  <li>setting the debug config to junit5, with the result that a message window pops up: "No tests found with test runner 'JUnit 5'.</li>
  <li>setting the debug config to junit5 and selecting 'Run all tests in the selected project, package or folder:' which - surprisingly - is working, but I cannot select the workspace root, which means I can never select all projects, and this setup will only find the tests in the suit's project and the selected project, but not the rest.</li>
  </ul>
  
  <p>I found multiple bugs referenced for older versions of eclipse displaying similar symptoms, but since I am running a very recent version, I suppose those should not apply anymore. Also I tried most of the workarounds suggested without success.</p>