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from collections.abc import Iterable
from concurrent import futures
import pytest
from multimethod import multidispatch, multimethod, signature, DispatchError
def test_signature():
with pytest.raises(TypeError):
signature([list]) <= signature([None])
# roshambo
rock, paper, scissors = (type('', (), {}) for _ in range(3))
@multimethod
def roshambo(left, right):
return 'tie'
@roshambo.register(scissors, rock)
@roshambo.register(rock, scissors)
def _(left, right):
return 'rock smashes scissors'
@roshambo.register(paper, scissors)
@roshambo.register(scissors, paper)
def _(left, right):
return 'scissors cut paper'
@roshambo.register(rock, paper)
@roshambo.register(paper, rock)
def _(left, right):
return 'paper covers rock'
def test_roshambo():
assert roshambo.__name__ == 'roshambo'
r, p, s = rock(), paper(), scissors()
assert len(roshambo) == 7
assert roshambo(r, p) == 'paper covers rock'
assert roshambo(p, r) == 'paper covers rock'
assert roshambo(r, s) == 'rock smashes scissors'
assert roshambo(p, s) == 'scissors cut paper'
assert roshambo(r, r) == 'tie'
assert len(roshambo) == 8
del roshambo[()]
del roshambo[rock, paper]
assert len(roshambo) == 5
with pytest.raises(DispatchError, match="0 methods"):
roshambo(r, r)
r = roshambo.copy()
assert isinstance(r, multimethod)
assert r == roshambo
# methods
class cls:
method = multidispatch(lambda self, other: None)
@method.register(Iterable, object)
def _(self, other):
return 'left'
@method.register(object, Iterable)
def _(self, other):
return 'right'
def test_cls():
obj = cls()
assert obj.method(None) is cls.method(None, None) is None
assert obj.method('') == 'right'
assert cls.method('', None) == 'left'
with pytest.raises(DispatchError, match="2 methods"):
cls.method('', '')
cls.method[object, Iterable] = cls.method[Iterable, object]
assert cls.method('', '') == 'left'
def test_arguments():
def func(a, b: int, /, c: int = 0, d=None, *, f: int): ...
assert signature.from_hints(func) == (object, int, int)
@multidispatch
def func(arg: ...): ...
def test_defaults():
def func(a: int, b: float = 0.0):
return b
assert signature.from_hints(func) == (int, float)
method = multimethod(func)
assert method(1) == 0.0
assert method(0, 1.0) == method(0, b=1.0) == 1.0
with pytest.raises(DispatchError, match="0 methods"):
method(0, 0)
assert multidispatch(func)(0, b=1)
assert multimethod(bool)(1)
@pytest.mark.benchmark
def test_keywords():
@multidispatch
def func(arg):
pass
@func.register
def _(arg: int):
return int
@func.register
def _(arg: int, extra: float):
return float
assert func(0) is func(arg=0) is int
assert func(0, 0.0) is func(arg=0, extra=0.0) is float
def test_concurrency():
@multimethod
def func(arg: int): ...
submit = futures.ThreadPoolExecutor().submit
args = [type('', (int,), {})() for _ in range(500)]
fs = [submit(func, arg) for arg in args]
assert all(future.result() is None for future in fs)
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