@Test
public void testGetEmrClusterDefinitionKeysNamespaceNoExists()
{

    // Mock the external calls.
    when(namespaceDao.getNamespaceByCd(NAMESPACE)).thenReturn(null);
    // Call the method under test.
    List<EmrClusterDefinitionKey> result = emrClusterDefinitionDaoHelper.getEmrClusterDefinitionKeys(NAMESPACE);
    // Verify the external calls.
    verify(namespaceDao).getNamespaceByCd(NAMESPACE);
    verifyNoMoreInteractionsHelper();
    // Validate the result.
    assertNotNull(result);
    assertEquals(0, result.size());
}