Bug 49484 "Errorless" Launch Config fails [JUnit]
Create a JUnit Launch configuration. On the Test tab 1) Be Sure "Project" is an empty field. 2) Select "Run all tests in the selected project, package or source folder". 3) Select the Project to search for tests. 4) Click Run The Progress view shows "ERROR: Launch: invalid project specified" If you specify the Project field, even without "Run a single test" being selected, it works. I don't know what will happen if the Project doesn't match the selection in "Run all tests..." 3.0 M6
org.eclipse.jdt.junit/src/org/eclipse/jdt/internal/junit/launcher/JUnitMainTab.java
acceptedClasses= new Class[] { IJavaModel.class, IPackageFragmentRoot.class, IJavaProject.class, IPackageFragment.class };
		ViewerFilter filter= new TypedViewerFilter(acceptedClasses) {
			public boolean select(Viewer viewer, Object parent, Object element) {
				return super.select(viewer, parent, element);
			}
		};		
		StandardJavaElementContentProvider provider= new StandardJavaElementContentProvider();
		ILabelProvider labelProvider= new JavaElementLabelProvider(JavaElementLabelProvider.SHOW_DEFAULT); 
		ElementTreeSelectionDialog dialog= new ElementTreeSelectionDialog(getShell(), labelProvider, provider);
		dialog.setValidator(validator);
		dialog.setSorter(new JavaElementSorter());
		dialog.setTitle(JUnitMessages.getString("JUnitMainTab.folderdialog.title"));  
		dialog.setMessage(JUnitMessages.getString("JUnitMainTab.folderdialog.message"));  
		dialog.addFilter(filter);
		dialog.setInput(JavaCore.create(getWorkspaceRoot()));
		dialog.setInitialSelection(initElement);
		dialog.setAllowMultiple(false);
		
		if (dialog.open() == Window.OK) {
			Object element= dialog.getFirstResult();
			return (IJavaElement)element;
		}
		return null;
	}
	
	private String getPresentationName(IJavaElement element) {
		return fJavaElementLabelProvider.getText(element);
	}
}