pybind11/tests/test_inheritance.py
Dean Moldovan b4498ef44d Add py::isinstance<T>(obj) for generalized Python type checking
Allows checking the Python types before creating an object instead of
after. For example:
```c++
auto l = list(ptr, true);
if (l.check())
   // ...
```
The above is replaced with:
```c++
if (isinstance<list>(ptr)) {
    auto l = reinterpret_borrow(ptr);
    // ...
}
```

This deprecates `py::object::check()`. `py::isinstance()` covers the
same use case, but it can also check for user-defined types:
```c++
class Pet { ... };
py::class_<Pet>(...);

m.def("is_pet", [](py::object obj) {
    return py::isinstance<Pet>(obj); // works as expected
});
```
2016-11-17 08:55:42 +01:00

56 lines
2.1 KiB
Python

import pytest
def test_inheritance(msg):
from pybind11_tests import Pet, Dog, Rabbit, Hamster, dog_bark, pet_name_species
roger = Rabbit('Rabbit')
assert roger.name() + " is a " + roger.species() == "Rabbit is a parrot"
assert pet_name_species(roger) == "Rabbit is a parrot"
polly = Pet('Polly', 'parrot')
assert polly.name() + " is a " + polly.species() == "Polly is a parrot"
assert pet_name_species(polly) == "Polly is a parrot"
molly = Dog('Molly')
assert molly.name() + " is a " + molly.species() == "Molly is a dog"
assert pet_name_species(molly) == "Molly is a dog"
fred = Hamster('Fred')
assert fred.name() + " is a " + fred.species() == "Fred is a rodent"
assert dog_bark(molly) == "Woof!"
with pytest.raises(TypeError) as excinfo:
dog_bark(polly)
assert msg(excinfo.value) == """
dog_bark(): incompatible function arguments. The following argument types are supported:
1. (arg0: m.Dog) -> str
Invoked with: <m.Pet object at 0>
"""
def test_automatic_upcasting():
from pybind11_tests import return_class_1, return_class_2, return_class_n, return_none
assert type(return_class_1()).__name__ == "DerivedClass1"
assert type(return_class_2()).__name__ == "DerivedClass2"
assert type(return_none()).__name__ == "NoneType"
# Repeat these a few times in a random order to ensure no invalid caching is applied
assert type(return_class_n(1)).__name__ == "DerivedClass1"
assert type(return_class_n(2)).__name__ == "DerivedClass2"
assert type(return_class_n(0)).__name__ == "BaseClass"
assert type(return_class_n(2)).__name__ == "DerivedClass2"
assert type(return_class_n(2)).__name__ == "DerivedClass2"
assert type(return_class_n(0)).__name__ == "BaseClass"
assert type(return_class_n(1)).__name__ == "DerivedClass1"
def test_isinstance():
from pybind11_tests import test_isinstance, Pet, Dog
objects = [tuple(), dict(), Pet("Polly", "parrot")] + [Dog("Molly")] * 4
expected = (True, True, True, True, True, False, False)
assert test_isinstance(objects) == expected