pybind11/tests/test_methods_and_attributes.py
Dean Moldovan 03f627ebb1 Make reference(_internal) the default return value policy for properties (#473)
* Make reference(_internal) the default return value policy for properties

Before this, all `def_property*` functions used `automatic` as their
default return value policy. This commit makes it so that:

 * Non-static properties use `reference_interal` by default, thus
   matching `def_readonly` and `def_readwrite`.

 * Static properties use `reference` by default, thus matching
   `def_readonly_static` and `def_readwrite_static`.

In case `cpp_function` is passed to any `def_property*`, its policy will
be used instead of any defaults. User-defined arguments in `extras`
still have top priority and will override both the default policies and
the ones from `cpp_function`.

Resolves #436.

* Almost always use return_value_policy::move for rvalues

For functions which return rvalues or rvalue references, the only viable
return value policies are `copy` and `move`. `reference(_internal)` and
`take_ownership` would take the address of a temporary which is always
an error.

This commit prevents possible user errors by overriding the bad rvalue
policies with `move`. Besides `move`, only `copy` is allowed, and only
if it's explicitly selected by the user.

This is also a necessary safety feature to support the new default
return value policies for properties: `reference(_internal)`.
2016-11-01 11:44:57 +01:00

189 lines
5.3 KiB
Python

import pytest
from pybind11_tests import ExampleMandA, ConstructorStats
def test_methods_and_attributes():
instance1 = ExampleMandA()
instance2 = ExampleMandA(32)
instance1.add1(instance2)
instance1.add2(instance2)
instance1.add3(instance2)
instance1.add4(instance2)
instance1.add5(instance2)
instance1.add6(32)
instance1.add7(32)
instance1.add8(32)
instance1.add9(32)
instance1.add10(32)
assert str(instance1) == "ExampleMandA[value=320]"
assert str(instance2) == "ExampleMandA[value=32]"
assert str(instance1.self1()) == "ExampleMandA[value=320]"
assert str(instance1.self2()) == "ExampleMandA[value=320]"
assert str(instance1.self3()) == "ExampleMandA[value=320]"
assert str(instance1.self4()) == "ExampleMandA[value=320]"
assert str(instance1.self5()) == "ExampleMandA[value=320]"
assert instance1.internal1() == 320
assert instance1.internal2() == 320
assert instance1.internal3() == 320
assert instance1.internal4() == 320
assert instance1.internal5() == 320
assert instance1.value == 320
instance1.value = 100
assert str(instance1) == "ExampleMandA[value=100]"
cstats = ConstructorStats.get(ExampleMandA)
assert cstats.alive() == 2
del instance1, instance2
assert cstats.alive() == 0
assert cstats.values() == ["32"]
assert cstats.default_constructions == 1
assert cstats.copy_constructions == 3
assert cstats.move_constructions >= 1
assert cstats.copy_assignments == 0
assert cstats.move_assignments == 0
def test_properties():
from pybind11_tests import TestProperties
instance = TestProperties()
assert instance.def_readonly == 1
with pytest.raises(AttributeError):
instance.def_readonly = 2
instance.def_readwrite = 2
assert instance.def_readwrite == 2
assert instance.def_property_readonly == 2
with pytest.raises(AttributeError):
instance.def_property_readonly = 3
instance.def_property = 3
assert instance.def_property == 3
def test_static_properties():
from pybind11_tests import TestProperties as Type
assert Type.def_readonly_static == 1
with pytest.raises(AttributeError):
Type.def_readonly_static = 2
Type.def_readwrite_static = 2
assert Type.def_readwrite_static == 2
assert Type.def_property_readonly_static == 2
with pytest.raises(AttributeError):
Type.def_property_readonly_static = 3
Type.def_property_static = 3
assert Type.def_property_static == 3
@pytest.mark.parametrize("access", ["ro", "rw", "static_ro", "static_rw"])
def test_property_return_value_policies(access):
from pybind11_tests import TestPropRVP
if not access.startswith("static"):
obj = TestPropRVP()
else:
obj = TestPropRVP
ref = getattr(obj, access + "_ref")
assert ref.value == 1
ref.value = 2
assert getattr(obj, access + "_ref").value == 2
ref.value = 1 # restore original value for static properties
copy = getattr(obj, access + "_copy")
assert copy.value == 1
copy.value = 2
assert getattr(obj, access + "_copy").value == 1
copy = getattr(obj, access + "_func")
assert copy.value == 1
copy.value = 2
assert getattr(obj, access + "_func").value == 1
def test_property_rvalue_policy():
"""When returning an rvalue, the return value policy is automatically changed from
`reference(_internal)` to `move`. The following would not work otherwise."""
from pybind11_tests import TestPropRVP
instance = TestPropRVP()
o = instance.rvalue
assert o.value == 1
o = TestPropRVP.static_rvalue
assert o.value == 1
def test_dynamic_attributes():
from pybind11_tests import DynamicClass, CppDerivedDynamicClass
instance = 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(DynamicClass)
assert cstats.alive() == 1
del instance
assert cstats.alive() == 0
# Derived classes should work as well
class PythonDerivedDynamicClass(DynamicClass):
pass
for cls in CppDerivedDynamicClass, PythonDerivedDynamicClass:
derived = cls()
derived.foobar = 100
assert derived.foobar == 100
assert cstats.alive() == 1
del derived
assert cstats.alive() == 0
def test_cyclic_gc():
from pybind11_tests import DynamicClass
# One object references itself
instance = DynamicClass()
instance.circular_reference = instance
cstats = ConstructorStats.get(DynamicClass)
assert cstats.alive() == 1
del instance
assert cstats.alive() == 0
# Two object reference each other
i1 = DynamicClass()
i2 = DynamicClass()
i1.cycle = i2
i2.cycle = i1
assert cstats.alive() == 2
del i1, i2
assert cstats.alive() == 0