blob: cff4e948bcbe8e7cc8e6ddf545d57c7f6ef74fee [file] [log] [blame]
# SPDX-License-Identifier: MIT
"""
Tests for `__init_subclass__` related functionality.
"""
import attr
def test_init_subclass_vanilla(slots):
"""
`super().__init_subclass__` can be used if the subclass is not an attrs
class both with dict and slotted classes.
"""
@attr.s(slots=slots)
class Base:
def __init_subclass__(cls, param, **kw):
super().__init_subclass__(**kw)
cls.param = param
class Vanilla(Base, param="foo"):
pass
assert "foo" == Vanilla().param
def test_init_subclass_attrs():
"""
`__init_subclass__` works with attrs classes as long as slots=False.
"""
@attr.s(slots=False)
class Base:
def __init_subclass__(cls, param, **kw):
super().__init_subclass__(**kw)
cls.param = param
@attr.s
class Attrs(Base, param="foo"):
pass
assert "foo" == Attrs().param
def test_init_subclass_slots_workaround():
"""
`__init_subclass__` works with modern APIs if care is taken around classes
existing twice.
"""
subs = {}
@attr.define
class Base:
def __init_subclass__(cls):
subs[cls.__qualname__] = cls
@attr.define
class Sub1(Base):
x: int
@attr.define
class Sub2(Base):
y: int
assert (Sub1, Sub2) == tuple(subs.values())