private KerberosConfigurationDescriptor createMockConfigurationDescriptor(Map<String, String> properties) {
    KerberosConfigurationDescriptor descriptor = createMock(KerberosConfigurationDescriptor.class);
    expect(descriptor.getProperties()).andReturn(properties).anyTimes();
    return descriptor;
  }
Test that a Kerberos Descriptor that contains a Service with 0 Components does not raise any exceptions.
ambari-server/src/test/java/org/apache/ambari/server/controller/KerberosHelperTest.java