def METHOD_NAME(self):
    '''
    Tests to ensure correct error are raised when
    i) strain data is missing
    ii) Strain data lacks critical attribute
    '''
    # No strain data
    with self.assertRaises(ValueError) as ae:
        self.model.get_secondary_strain_data()
    self.assertEqual(str(ae.exception),
                     'Strain data not input or incorrectly formatted')
    # Strain data missing critical attribute - e.g. exy
    self.data = {'longitude': np.array([10., 20., 30.]),
                 'latitude': np.array([10., 20., 30.]),
                 'exx': np.array([1E-9, 20E-9, 25E-9]),
                 'eyy': np.array([1E-9, 20E-9, 25E-9])}
    with self.assertRaises(ValueError) as ae:
        self.model.get_secondary_strain_data(self.data)
    self.assertEqual(str(ae.exception),
                     'Essential strain information exy missing!')