public void launch(ISelection selection, String mode) {
      if(selection instanceof TreeSelection && ((TreeSelection)selection).getFirstElement() instanceof IFile) {
            //code to get the generated java file using the test file selection 
            
            ICompilationUnit javaFile = (ICompilationUnit) JavaCore.create(testClassFile);
	    Object[] segments = {javaFile};
	    TreePath treePath = new TreePath(segments);
	    TreeSelection javaFileSelection= new TreeSelection(treePath);
	    JUnitLaunchShortcut jUnitLaunchShortcut = new JUnitLaunchShortcut();
	    jUnitLaunchShortcut.launch((ISelection)javaFileSelection, mode);
}

public void launch(IEditorPart editor, String mode) { 
      if(editor instanceof XtextEditor) {
            //code to get the generated java file using the test editor
           
            ICompilationUnit javaFile = (ICompilationUnit) JavaCore.create(testClassFile);
	    try {
	          CompilationUnitEditor javaEditor = (CompilationUnitEditor) JavaUI.openInEditor(javaFile);
	          JavaElementDelegate javaElementDelegate =editor.getAdapter(JavaElementDelegateJunitLaunch.class);
					
	          //other types of implementation
	          //JavaElementDelegate javaElementDelegate = Adapters.adapt(editor, JavaElementDelegateJunitLaunch.class);
	          //JavaElementDelegate javaElementDelegate = Adapters.adapt(javaEditor, JavaElementDelegateJunitLaunch.class);
	          //JavaElementDelegate javaElementDelegate = javaEditor.getAdapter(JavaElementDelegateJunitLaunch.class);
				
	          JUnitLaunchShortcut jUnitLaunchShortcut = new JUnitLaunchShortcut();
	          jUnitLaunchShortcut.launch(new StructuredSelection(javaElementDelegate), mode);
				
	          //other types of implementation
	          //jUnitLaunchShortcut.launch(editor, mode);
	          //jUnitLaunchShortcut.launch(javaEditor, mode);
            } catch (PartInitException | JavaModelException e) {
		e.printStackTrace();
	    }
     }
}