Bug 41798 New JUnit Plug-in test requires test suites to extend Test
The new JUnit plug-in test seems to require test suites to extend TestSuite. Otherwise an error is reported in the launch config dialog. It is however still possible to launch a test suite by opening it in the editor and choosing Run->Run As->New JUnit Plug-in Test To reproduce, try to run (and configure) the JDT UI AllAllTests testsuite.
org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/launcher/JUnitMainTab.java
*/
	public boolean isValid(ILaunchConfiguration config) {		
		return getErrorMessage() == null;
	}
	
	private void testModeChanged() {
		boolean isSingleTestMode= fTestRadioButton.getSelection();
		setEnableSingleTestGroup(isSingleTestMode);
		setEnableContainerTestGroup(!isSingleTestMode);
		validatePage();
		updateLaunchConfigurationDialog();
	}
	private void validatePage() {
		setErrorMessage(null);
		setMessage(null);
		
		if (fTestContainerRadioButton.getSelection()) {
			if (fContainerElement == null)
				setErrorMessage(JUnitMessages.getString("JUnitMainTab.error.noContainer")); 
			return;
		} 
		
		String projectName = fProjText.getText().trim();
		if (projectName.length() == 0) {
			setErrorMessage(JUnitMessages.getString("JUnitMainTab.error.projectnotdefined")); 
			return;
		}
			
		IProject project = getWorkspaceRoot().getProject(projectName);
		if (!project.exists()) {