def test_has_attribute_predicate():
def f(x):
return x.count(2)
g = guard(Any.has('count'))(f)
with pytest.raises(NoMatch):
g({})
with pytest.raises(NoMatch):
g(1)
assert g((1, 2, 2, 3)) == 2
def test_with_regex_matching():
def f(s):
return s
g = guard(Any.re('A|B'))(f)
with pytest.raises(NoMatch):
g('Cat')
with pytest.raises(NoMatch):
g('CAT')
assert g('About') == 'About'
def test_check_varargs():
def count_args(*args):
return len(args)
g = guard(1, Any.args(Any(int)))(count_args)
with pytest.raises(NoMatch):
g(0)
with pytest.raises(NoMatch):
g(1, 'a')
with pytest.raises(NoMatch):
g(1, *(['a'] * 20))
assert g(1, 2, 3) == 3
assert g(*([1] * 20)) == 20
def test_has_with_predicate():
X = type('X', (object, ), {'value': None})
def f(x):
return x.value
g = guard(Any.has(value=Any(int)))(f)
with pytest.raises(NoMatch):
g('123')
with pytest.raises(NoMatch):
x = X()
x.value = '321'
g(x)
x = X()
x.value = 321
assert g(x) == 321
def test_explicitly_combined_patterns():
@guard(Any.of(0, 1))
def fib0(n):
return 1
@guard(Any(int))
def fib(n):
return fib(n - 1) + fib(n - 2)
fib = Pattern(fib0, fib)
assert fib(0) == 1
assert fib(1) == 1
assert fib(2) == 2
assert fib(3) == 3
with pytest.raises(NoMatch):
fib('not a number')
