@Override
  public void process(String host, String value, ApplicationId applicationId,
      ApplicationSubmissionContext submissionContext) {
    submissionContext.setNodeLabelExpression(value);
  }
@Test
  public void testNodeLabelProcessor() {
    ContextProcessor nodeLabelProcessor = new NodeLabelProcessor();
    ApplicationId app = ApplicationId.newInstance(123456, 111);
    ApplicationSubmissionContext applicationSubmissionContext =
        mock(ApplicationSubmissionContext.class);
    when(applicationSubmissionContext.getApplicationId()).thenReturn(app);
    nodeLabelProcessor.process("host.cluster2.com", "foo", app,
        applicationSubmissionContext);
    verify(applicationSubmissionContext, times(1))
        .setNodeLabelExpression("foo");
  }