def test_compose():
f = restrict_arity(Mock(), 1)
g = restrict_arity(Mock(), 3)
h = compose(f, g)
result = h(1, 2, 3)
g.assert_called_once_with(1, 2, 3)
f.assert_called_once_with(g.return_value)
assert result is f.return_value
def test_parallel_combine():
h = restrict_arity(Mock(), 2)
f = restrict_arity(Mock(), 3)
g = restrict_arity(Mock(), 3)
c = parallel_combine(h, f, g)
result = c(1, 2, 3)
f.assert_called_once_with(1, 2, 3)
g.assert_called_once_with(1, 2, 3)
h.assert_called_once_with(f.return_value, g.return_value)
assert result is h.return_value
def test_spread_combine_with_g_vararg():
h, f, g = Mock(), Mock(), Mock()
restrict_arity(f, 2)
restrict_arity(g, Arity(0, False))
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(2, False)
def test_spread_combine():
h, f, g = Mock(), Mock(), Mock()
restrict_arity(f, 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 is h.return_value
assert get_arity(c) == Arity(5)
def test_iterate_feeds_output_back_to_function():
func = restrict_arity(Mock(), 1)
iterate(3)(func)("input")
func.assert_has_calls(
[call("input"),
call(func.return_value),
call(func.return_value)])
def test_permute_arguments():
func = restrict_arity(Mock(), 4)
f1 = permute_arguments(1, 2, 0, 3)
f2 = f1(func)
r = f2('a', 'b', 'c', 'd')
func.assert_called_once_with('b', 'c', 'a', 'd')
assert r is func.return_value
def test_curry_multple_arguments():
func = restrict_arity(Mock(), 5)
f1 = curry_arguments(1, 3)
f2 = f1('a', 'b', 'c')
f3 = f2(func)
r = f3('x', 'y')
func.assert_called_once_with('a', 'x', 'b', 'y', 'c')
assert r is func.return_value
def test_discard_one_argument():
dc = discard_arguments(1)
func = restrict_arity(Mock(), 2)
f = dc(func)
r = f(1, 2, 3)
func.assert_called_once_with(1, 3)
assert r is func.return_value
def test_curry_argument():
func = restrict_arity(Mock(), 4)
f1 = curry_arguments(2)
f2 = f1('a', 'b', 'c')
f3 = f2(func)
r = f3('d')
func.assert_called_once_with('a', 'b', 'd', 'c')
assert r is func.return_value
def test_discard_keyword_argument():
dc = discard_arguments('b')
func = restrict_arity(Mock(), 2)
f = dc(func)
r = f(1, b=2, c=3)
func.assert_called_once_with(1, c=3)
assert r is func.return_value
def test_discard_multiple_arguments():
dc = discard_arguments(0, 2, 4)
func = restrict_arity(Mock(), 2)
f = dc(func)
r = f(1, 2, 3, 4, 5)
func.assert_called_once_with(2, 4)
assert r is func.return_value
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_iterate_calls_function_n_times():
func = restrict_arity(Mock(), 1)
iterate(3)(func)("input")
assert func.call_count == 3
def test_iterate_once_calls_the_function():
func = restrict_arity(Mock(), 1)
result = iterate(1)(func)(42)
func.assert_called_once_with(42)
assert result is func.return_value
def test_composition_checks_arity():
f = restrict_arity(Mock(), 1)
h = compose(f, lambda x, y: 0)
with pytest.raises(TypeError, match="argument"):
compose(f, h)()
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)
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)