def test_spread_combine_with_f_vararg():
h, f, g = Mock(), Mock(), Mock()
restrict_arity(f, Arity(1, 2))
restrict_arity(g, 3)
c = spread_combine(h, f, g)
result = c(1, 2, 3, 4, 5)
f.assert_called_once_with(1, 2)
g.assert_called_once_with(3, 4, 5)
h.assert_called_once_with(f.return_value, g.return_value)
assert result == h.return_value
assert get_arity(c) == Arity(4, 5)
def test_get_arity_of_arbitrary_function():
assert get_arity(lambda: None) == Arity(0)
assert get_arity(lambda x: None) == Arity(1)
assert get_arity(lambda x, y, z: None) == Arity(3)
assert get_arity(lambda x, y, z=0: None) == Arity(2, 3)
assert get_arity(lambda *args: None) == Arity(0, False)
assert get_arity(lambda **kwargs: None) == Arity(0)
def test_parallel_combine_arity_equals_arity_of_f_and_g():
h = restrict_arity(Mock(), 2)
p = parallel_combine(h, lambda x, y, z: 0, lambda x, y, z: 0)
assert get_arity(p) == Arity(3)
def test_composition_arity_equals_arity_of_g():
f = restrict_arity(Mock(), 1)
h = compose(f, lambda x, y: 0)
assert get_arity(h) == Arity(2)
def test_compatibility_with_unbounded_arity():
arity = Arity(2, False)
assert not arity.is_compatible(1)
assert arity.is_compatible(2)
assert arity.is_compatible(3)
assert arity.is_compatible(4)
def test_compatibility_with_maximum_arity():
arity = Arity(2, 3)
assert not arity.is_compatible(1)
assert arity.is_compatible(2)
assert arity.is_compatible(3)
assert not arity.is_compatible(4)
def test_compatibility_with_fixed_arity():
arity = Arity(2)
assert not arity.is_compatible(1)
assert arity.is_compatible(2)
assert not arity.is_compatible(3)
def test_spread_combine_f_and_g_cant_both_be_vararg():
h, f, g = Mock(), Mock(), Mock()
restrict_arity(f, Arity(2, 3))
restrict_arity(g, Arity(2, 3))
with pytest.raises(AssertionError):
spread_combine(h, f, g)