from walsh.walsh import nonlinearity


def test_nonlinearity_linear_function():
    assert nonlinearity("x1 XOR x2") == 0


def test_nonlinearity_or():
    assert nonlinearity("x1 OR x2") == 1


def test_nonlinearity_majority():
    assert nonlinearity("x1*x2 XOR x1*x3 XOR x2*x3") == 2