def test_weakset_init():
k = C()
# init from a list
s = WeakSet([k])
assert k in s
# init from another weakset
s2 = WeakSet(s)
assert k in s2
def test_weakset():
s = WeakSet()
k = C()
s.add(k)
assert len(s) == 1
assert k in s
s.discard(k)
assert len(s) == 0
assert k not in s
s.add(k)
del k
assert len(s) == 0
def test_weakset():
s = WeakSet()
k = C()
s.add(k)
assert len(s) == 1
assert k in s
s.discard(k)
assert len(s) == 0
assert k not in s
s.add(k)
del k
assert len(s) == 0