Bug 12002 TestCase wizard: error when pressing finish with an empty test name
the finish button should be disabled when the test name field is empty
org.eclipse.jdt.junit/src/org/eclipse/jdt/junit/wizards/NewTestCaseCreationWizardPage.java
if (root == null) 
			return null;
		IJavaElement[] elements= new IJavaElement[] { root.getJavaProject() };
		IJavaSearchScope scope= SearchEngine.createJavaSearchScope(elements);
		
		IType type= null;
		try {
			SelectionDialog dialog= JavaUI.createTypeDialog(getShell(), getWizard().getContainer(), scope, IJavaElementSearchConstants.CONSIDER_CLASSES, false, null);
			dialog.setTitle(Messages.getString("NewTestClassWizPage.class_to_test.dialog.title")); 
			dialog.setMessage(Messages.getString("NewTestClassWizPage.class_to_test.dialog.message")); 
			dialog.open();
			if (dialog.getReturnCode() != SelectionDialog.OK)
				return type;
			else {
				Object[] resultArray= dialog.getResult();
				type= (IType) resultArray[0];
			}
		} catch (JavaModelException e) {
			JUnitPlugin.log(e);
		}
		return type;
	}
	protected IStatus classToTestClassChanged() {
		fClassToTestButton.setEnabled(getPackageFragmentRoot() != null);
		IStatus status= validateClassToTest();
		return status;
	}
	/**
	 * Gets the content of the class to test text field.
	 */