def test_cyclic_gc():
# One object references itself
instance = m.DynamicClass()
instance.circular_reference = instance
cstats = ConstructorStats.get(m.DynamicClass)
assert cstats.alive() == 1
del instance
assert cstats.alive() == 0
# Two object reference each other
i1 = m.DynamicClass()
i2 = m.DynamicClass()
i1.cycle = i2
i2.cycle = i1
assert cstats.alive() == 2
del i1, i2
assert cstats.alive() == 0
def test_dynamic_attributes():
instance = m.DynamicClass()
assert not hasattr(instance, "foo")
assert "foo" not in dir(instance)
# Dynamically add attribute
instance.foo = 42
assert hasattr(instance, "foo")
assert instance.foo == 42
assert "foo" in dir(instance)
# __dict__ should be accessible and replaceable
assert "foo" in instance.__dict__
instance.__dict__ = {"bar": True}
assert not hasattr(instance, "foo")
assert hasattr(instance, "bar")
with pytest.raises(TypeError) as excinfo:
instance.__dict__ = []
assert str(
excinfo.value) == "__dict__ must be set to a dictionary, not a 'list'"
cstats = ConstructorStats.get(m.DynamicClass)
assert cstats.alive() == 1
del instance
assert cstats.alive() == 0
# Derived classes should work as well
class PythonDerivedDynamicClass(m.DynamicClass):
pass
for cls in m.CppDerivedDynamicClass, PythonDerivedDynamicClass:
derived = cls()
derived.foobar = 100
assert derived.foobar == 100
assert cstats.alive() == 1
del derived
assert cstats.alive() == 0
