test_opaque_types.py

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from __future__ import annotations
 
import pytest
 
from pybind11_tests import ConstructorStats, UserType
from pybind11_tests import opaque_types as m
 
 
def test_string_list():
    lst = m.StringList()
    lst.push_back("Element 1")
    lst.push_back("Element 2")
    assert m.print_opaque_list(lst) == "Opaque list: [Element 1, Element 2]"
    assert lst.back() == "Element 2"
 
    for i, k in enumerate(lst, start=1):
        assert k == f"Element {i}"
    lst.pop_back()
    assert m.print_opaque_list(lst) == "Opaque list: [Element 1]"
 
    cvp = m.ClassWithSTLVecProperty()
    assert m.print_opaque_list(cvp.stringList) == "Opaque list: []"
 
    cvp.stringList = lst
    cvp.stringList.push_back("Element 3")
    assert m.print_opaque_list(cvp.stringList) == "Opaque list: [Element 1, Element 3]"
 
 
def test_pointers(msg):
    living_before = ConstructorStats.get(UserType).alive()
    assert m.get_void_ptr_value(m.return_void_ptr()) == 0x1234
    assert m.get_void_ptr_value(UserType())  # Should also work for other C++ types
    assert ConstructorStats.get(UserType).alive() == living_before
 
    with pytest.raises(TypeError) as excinfo:
        m.get_void_ptr_value([1, 2, 3])  # This should not work
    assert (
        msg(excinfo.value)
        == """
        get_void_ptr_value(): incompatible function arguments. The following argument types are supported:
            1. (arg0: capsule) -> int
 
        Invoked with: [1, 2, 3]
    """
    )
 
    assert m.return_null_str() is None
    assert m.get_null_str_value(m.return_null_str()) is not None
 
    ptr = m.return_unique_ptr()
    assert "StringList" in repr(ptr)
    assert m.print_opaque_list(ptr) == "Opaque list: [some value]"
 
 
def test_unions():
    int_float_union = m.IntFloat()
    int_float_union.i = 42
    assert int_float_union.i == 42
    int_float_union.f = 3.0
    assert int_float_union.f == 3.0