# This test code was written by the `hypothesis.extra.ghostwriter` module
# and is provided under the Creative Commons Zero public domain dedication.

import operator
from hypothesis import given, strategies as st

# TODO: replace st.nothing() with an appropriate strategy

matmul_operands = st.nothing()


@given(a=matmul_operands, b=matmul_operands, c=matmul_operands)
def test_associative_binary_operation_matmul(a, b, c):
    left = operator.matmul(a, operator.matmul(b, c))
    right = operator.matmul(operator.matmul(a, b), c)
    assert left == right, (left, right)


@given(a=matmul_operands)
def test_identity_binary_operation_matmul(a):
    identity = "identity element here"
    assert a == operator.matmul(a, identity)
    assert a == operator.matmul(identity, a)


@given(a=matmul_operands, b=matmul_operands, c=matmul_operands)
def test_add_distributes_over_binary_operation_matmul(a, b, c):
    left = operator.matmul(a, operator.add(b, c))
    ldist = operator.add(operator.matmul(a, b), operator.matmul(a, c))
    assert ldist == left, (ldist, left)

    right = operator.matmul(operator.add(a, b), c)
    rdist = operator.add(operator.matmul(a, c), operator.matmul(b, c))
    assert rdist == right, (rdist, right)
