pybind11/tests/test_copy_move.py

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import pytest
from pybind11_tests import has_optional
def test_lacking_copy_ctor():
from pybind11_tests import lacking_copy_ctor
with pytest.raises(RuntimeError) as excinfo:
lacking_copy_ctor.get_one()
assert "the object is non-copyable!" in str(excinfo.value)
def test_lacking_move_ctor():
from pybind11_tests import lacking_move_ctor
with pytest.raises(RuntimeError) as excinfo:
lacking_move_ctor.get_one()
assert "the object is neither movable nor copyable!" in str(excinfo.value)
def test_move_and_copy_casts():
"""Cast some values in C++ via custom type casters and count the number of moves/copies."""
from pybind11_tests import move_and_copy_casts, move_and_copy_cstats
cstats = move_and_copy_cstats()
c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
# The type move constructions/assignments below each get incremented: the move assignment comes
# from the type_caster load; the move construction happens when extracting that via a cast or
# loading into an argument.
assert move_and_copy_casts(3) == 18
assert c_m.copy_assignments + c_m.copy_constructions == 0
assert c_m.move_assignments == 2
assert c_m.move_constructions >= 2
assert c_mc.alive() == 0
assert c_mc.copy_assignments + c_mc.copy_constructions == 0
assert c_mc.move_assignments == 2
assert c_mc.move_constructions >= 2
assert c_c.alive() == 0
assert c_c.copy_assignments == 2
assert c_c.copy_constructions >= 2
assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
def test_move_and_copy_loads():
"""Call some functions that load arguments via custom type casters and count the number of
moves/copies."""
from pybind11_tests import (move_and_copy_cstats, move_only, move_or_copy, copy_only,
move_pair, move_tuple, copy_tuple, move_copy_nested)
cstats = move_and_copy_cstats()
c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
assert move_only(10) == 10 # 1 move, c_m
assert move_or_copy(11) == 11 # 1 move, c_mc
assert copy_only(12) == 12 # 1 copy, c_c
assert move_pair((13, 14)) == 27 # 1 c_m move, 1 c_mc move
assert move_tuple((15, 16, 17)) == 48 # 2 c_m moves, 1 c_mc move
assert copy_tuple((18, 19)) == 37 # 2 c_c copies
# Direct constructions: 2 c_m moves, 2 c_mc moves, 1 c_c copy
# Extra moves/copies when moving pairs/tuples: 3 c_m, 3 c_mc, 2 c_c
assert move_copy_nested((1, ((2, 3, (4,)), 5))) == 15
assert c_m.copy_assignments + c_m.copy_constructions == 0
assert c_m.move_assignments == 6
assert c_m.move_constructions == 9
assert c_mc.copy_assignments + c_mc.copy_constructions == 0
assert c_mc.move_assignments == 5
assert c_mc.move_constructions == 8
assert c_c.copy_assignments == 4
assert c_c.copy_constructions == 6
assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
@pytest.mark.skipif(not has_optional, reason='no <optional>')
def test_move_and_copy_load_optional():
"""Tests move/copy loads of std::optional arguments"""
from pybind11_tests import (move_and_copy_cstats, move_optional, move_or_copy_optional,
copy_optional, move_optional_tuple)
cstats = move_and_copy_cstats()
c_m, c_mc, c_c = cstats["MoveOnlyInt"], cstats["MoveOrCopyInt"], cstats["CopyOnlyInt"]
# The extra move/copy constructions below come from the std::optional move (which has to move
# its arguments):
assert move_optional(10) == 10 # c_m: 1 move assign, 2 move construct
assert move_or_copy_optional(11) == 11 # c_mc: 1 move assign, 2 move construct
assert copy_optional(12) == 12 # c_c: 1 copy assign, 2 copy construct
# 1 move assign + move construct moves each of c_m, c_mc, 1 c_c copy
# +1 move/copy construct each from moving the tuple
# +1 move/copy construct each from moving the optional (which moves the tuple again)
assert move_optional_tuple((3, 4, 5)) == 12
assert c_m.copy_assignments + c_m.copy_constructions == 0
assert c_m.move_assignments == 2
assert c_m.move_constructions == 5
assert c_mc.copy_assignments + c_mc.copy_constructions == 0
assert c_mc.move_assignments == 2
assert c_mc.move_constructions == 5
assert c_c.copy_assignments == 2
assert c_c.copy_constructions == 5
assert c_m.alive() + c_mc.alive() + c_c.alive() == 0
def test_private_op_new():
"""An object with a private `operator new` cannot be returned by value"""
import pybind11_tests as m
with pytest.raises(RuntimeError) as excinfo:
m.private_op_new_value()
assert "the object is neither movable nor copyable" in str(excinfo.value)
assert m.private_op_new_reference().value == 1
def test_move_fallback():
"""#389: rvp::move should fall-through to copy on non-movable objects"""
from pybind11_tests import get_moveissue1, get_moveissue2
m2 = get_moveissue2(2)
assert m2.value == 2
m1 = get_moveissue1(1)
assert m1.value == 1