def test_can_get_matrix_inverse(self, mock_det, mock_adjoint):
adjoint = Mock()
mock_adjoint.return_value = 3
mock_det.return_value = 0.25
matrix = Matrix([4, -3, 1], [2, -1, 2], [1, 5, 7])
self.assertEqual(matrix.inverse(), 12)
mock_adjoint.assert_called_with()
mock_det.assert_called_with()
def test_no_inverse_if_zero_det(self, mock_det):
mock_det.return_value = 0
matrix = Matrix([4, -3, 1], [2, -1, 2], [1, 5, 7])
with self.assertRaises(ValueError):
matrix.inverse()
