Method test_ufunc_override_mro

numpy/core/tests/test_umath.py:3245–3378

(self)

        assert_equal(res1[4], {'out': (a,)})

    def test_ufunc_override_mro(self):

        # Some multi arg functions for testing.
        def tres_mul(a, b, c):
            return a * b * c

        def quatro_mul(a, b, c, d):
            return a * b * c * d

        # Make these into ufuncs.
        three_mul_ufunc = np.frompyfunc(tres_mul, 3, 1)
        four_mul_ufunc = np.frompyfunc(quatro_mul, 4, 1)

        class A:
            def __array_ufunc__(self, func, method, *inputs, **kwargs):
                return "A"

        class ASub(A):
            def __array_ufunc__(self, func, method, *inputs, **kwargs):
                return "ASub"

        class B:
            def __array_ufunc__(self, func, method, *inputs, **kwargs):
                return "B"

        class C:
            def __init__(self):
                self.count = 0

            def __array_ufunc__(self, func, method, *inputs, **kwargs):
                self.count += 1
                return NotImplemented

        class CSub(C):
            def __array_ufunc__(self, func, method, *inputs, **kwargs):
                self.count += 1
                return NotImplemented

        a = A()
        a_sub = ASub()
        b = B()
        c = C()

        # Standard
        res = np.multiply(a, a_sub)
        assert_equal(res, "ASub")
        res = np.multiply(a_sub, b)
        assert_equal(res, "ASub")

        # With 1 NotImplemented
        res = np.multiply(c, a)
        assert_equal(res, "A")
        assert_equal(c.count, 1)
        # Check our counter works, so we can trust tests below.
        res = np.multiply(c, a)
        assert_equal(c.count, 2)

        # Both NotImplemented.