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attrs/tests/test_make.py

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# SPDX-License-Identifier: MIT
"""
Tests for `attr._make`.
"""
import copy
import functools
import gc
import inspect
import itertools
import sys
from operator import attrgetter
from typing import Generic, TypeVar
import pytest
from hypothesis import assume, given
from hypothesis.strategies import booleans, integers, lists, sampled_from, text
import attr
from attr import _config
from attr._compat import PY_3_10_PLUS, PY_3_14_PLUS
from attr._make import (
Attribute,
Factory,
_AndValidator,
_Attributes,
_ClassBuilder,
_CountingAttr,
_determine_attrib_eq_order,
_determine_attrs_eq_order,
_determine_whether_to_implement,
_transform_attrs,
and_,
fields,
fields_dict,
make_class,
validate,
)
from attr.exceptions import DefaultAlreadySetError, NotAnAttrsClassError
from .strategies import (
gen_attr_names,
list_of_attrs,
optional_bool,
simple_attrs,
simple_attrs_with_metadata,
simple_attrs_without_metadata,
simple_classes,
)
from .utils import simple_attr
attrs_st = simple_attrs.map(lambda c: Attribute.from_counting_attr("name", c))
@pytest.fixture(name="with_and_without_validation", params=[True, False])
def _with_and_without_validation(request):
"""
Run tests with and without validation enabled.
"""
attr.validators.set_disabled(request.param)
try:
yield
finally:
attr.validators.set_disabled(False)
class TestCountingAttr:
"""
Tests for `attr`.
"""
def test_returns_Attr(self):
"""
Returns an instance of _CountingAttr.
"""
a = attr.ib()
assert isinstance(a, _CountingAttr)
def test_validators_lists_to_wrapped_tuples(self):
"""
If a list is passed as validator, it's just converted to a tuple.
"""
def v1(_, __):
pass
def v2(_, __):
pass
a = attr.ib(validator=[v1, v2])
assert _AndValidator((v1, v2)) == a._validator
def test_validator_decorator_single(self):
"""
If _CountingAttr.validator is used as a decorator and there is no
decorator set, the decorated method is used as the validator.
"""
a = attr.ib()
@a.validator
def v():
pass
assert v == a._validator
@pytest.mark.parametrize(
"wrap", [lambda v: v, lambda v: [v], lambda v: and_(v)]
)
def test_validator_decorator(self, wrap):
"""
If _CountingAttr.validator is used as a decorator and there is already
a decorator set, the decorators are composed using `and_`.
"""
def v(_, __):
pass
a = attr.ib(validator=wrap(v))
@a.validator
def v2(self, _, __):
pass
assert _AndValidator((v, v2)) == a._validator
def test_default_decorator_already_set(self):
"""
Raise DefaultAlreadySetError if the decorator is used after a default
has been set.
"""
a = attr.ib(default=42)
with pytest.raises(DefaultAlreadySetError):
@a.default
def f(self):
pass
def test_default_decorator_sets(self):
"""
Decorator wraps the method in a Factory with pass_self=True and sets
the default.
"""
a = attr.ib()
@a.default
def f(self):
pass
assert Factory(f, True) == a._default
def make_tc():
class TransformC:
z = attr.ib()
y = attr.ib()
x = attr.ib()
a = 42
return TransformC
class TestTransformAttrs:
"""
Tests for `_transform_attrs`.
"""
def test_no_modifications(self):
"""
Does not attach __attrs_attrs__ to the class.
"""
C = make_tc()
_transform_attrs(C, None, False, False, True, None)
assert None is getattr(C, "__attrs_attrs__", None)
def test_normal(self):
"""
Transforms every `_CountingAttr` and leaves others (a) be.
"""
C = make_tc()
attrs, _, _ = _transform_attrs(C, None, False, False, True, None)
assert ["z", "y", "x"] == [a.name for a in attrs]
def test_empty(self):
"""
No attributes works as expected.
"""
@attr.s
class C:
pass
assert _Attributes(((), [], {})) == _transform_attrs(
C, None, False, False, True, None
)
def test_transforms_to_attribute(self):
"""
All `_CountingAttr`s are transformed into `Attribute`s.
"""
C = make_tc()
attrs, base_attrs, _ = _transform_attrs(
C, None, False, False, True, None
)
assert [] == base_attrs
assert 3 == len(attrs)
assert all(isinstance(a, Attribute) for a in attrs)
def test_conflicting_defaults(self):
"""
Raises `ValueError` if attributes with defaults are followed by
mandatory attributes.
"""
class C:
x = attr.ib(default=None)
y = attr.ib()
with pytest.raises(ValueError) as e:
_transform_attrs(C, None, False, False, True, None)
assert (
"No mandatory attributes allowed after an attribute with a "
"default value or factory. Attribute in question: Attribute"
"(name='y', default=NOTHING, validator=None, repr=True, "
"eq=True, eq_key=None, order=True, order_key=None, "
"hash=None, init=True, "
"metadata=mappingproxy({}), type=None, converter=None, "
"kw_only=False, inherited=False, on_setattr=None, alias=None)",
) == e.value.args
def test_kw_only(self):
"""
Converts all attributes, including base class' attributes, if `kw_only`
is provided. Therefore, `kw_only` allows attributes with defaults to
precede mandatory attributes.
Updates in the subclass *don't* affect the base class attributes.
"""
@attr.s
class B:
b = attr.ib()
for b_a in B.__attrs_attrs__:
assert b_a.kw_only is False
class C(B):
x = attr.ib(default=None)
y = attr.ib()
attrs, base_attrs, _ = _transform_attrs(
C, None, False, True, True, None
)
assert len(attrs) == 3
assert len(base_attrs) == 1
for a in attrs:
assert a.kw_only is True
for b_a in B.__attrs_attrs__:
assert b_a.kw_only is False
def test_these(self):
"""
If these is passed, use it and ignore body and base classes.
"""
class Base:
z = attr.ib()
class C(Base):
y = attr.ib()
attrs, base_attrs, _ = _transform_attrs(
C, {"x": attr.ib()}, False, False, True, None
)
assert [] == base_attrs
assert (simple_attr("x"),) == attrs
def test_these_leave_body(self):
"""
If these is passed, no attributes are removed from the body.
"""
@attr.s(init=False, these={"x": attr.ib()})
class C:
x = 5
assert 5 == C().x
assert "C(x=5)" == repr(C())
def test_these_ordered(self):
"""
If these is passed ordered attrs, their order respect instead of the
counter.
"""
b = attr.ib(default=2)
a = attr.ib(default=1)
@attr.s(these={"a": a, "b": b})
class C:
pass
assert "C(a=1, b=2)" == repr(C())
def test_multiple_inheritance_old(self):
"""
Old multiple inheritance attribute collection behavior is retained.
See #285
"""
@attr.s
class A:
a1 = attr.ib(default="a1")
a2 = attr.ib(default="a2")
@attr.s
class B(A):
b1 = attr.ib(default="b1")
b2 = attr.ib(default="b2")
@attr.s
class C(B, A):
c1 = attr.ib(default="c1")
c2 = attr.ib(default="c2")
@attr.s
class D(A):
d1 = attr.ib(default="d1")
d2 = attr.ib(default="d2")
@attr.s
class E(C, D):
e1 = attr.ib(default="e1")
e2 = attr.ib(default="e2")
assert (
"E(a1='a1', a2='a2', b1='b1', b2='b2', c1='c1', c2='c2', d1='d1', "
"d2='d2', e1='e1', e2='e2')"
) == repr(E())
def test_overwrite_proper_mro(self):
"""
The proper MRO path works single overwrites too.
"""
@attr.s(collect_by_mro=True)
class C:
x = attr.ib(default=1)
@attr.s(collect_by_mro=True)
class D(C):
x = attr.ib(default=2)
assert "D(x=2)" == repr(D())
def test_multiple_inheritance_proper_mro(self):
"""
Attributes are collected according to the MRO.
See #428
"""
@attr.s
class A:
a1 = attr.ib(default="a1")
a2 = attr.ib(default="a2")
@attr.s
class B(A):
b1 = attr.ib(default="b1")
b2 = attr.ib(default="b2")
@attr.s
class C(B, A):
c1 = attr.ib(default="c1")
c2 = attr.ib(default="c2")
@attr.s
class D(A):
d1 = attr.ib(default="d1")
d2 = attr.ib(default="d2")
@attr.s(collect_by_mro=True)
class E(C, D):
e1 = attr.ib(default="e1")
e2 = attr.ib(default="e2")
assert (
"E(a1='a1', a2='a2', d1='d1', d2='d2', b1='b1', b2='b2', c1='c1', "
"c2='c2', e1='e1', e2='e2')"
) == repr(E())
def test_mro(self):
"""
Attributes and methods are looked up the same way.
See #428
"""
@attr.s(collect_by_mro=True)
class A:
x = attr.ib(10)
def xx(self):
return 10
@attr.s(collect_by_mro=True)
class B(A):
y = attr.ib(20)
@attr.s(collect_by_mro=True)
class C(A):
x = attr.ib(50)
def xx(self):
return 50
@attr.s(collect_by_mro=True)
class D(B, C):
pass
d = D()
assert d.x == d.xx()
def test_inherited(self):
"""
Inherited Attributes have `.inherited` True, otherwise False.
"""
@attr.s
class A:
a = attr.ib()
@attr.s
class B(A):
b = attr.ib()
@attr.s
class C(B):
a = attr.ib()
c = attr.ib()
f = attr.fields
assert False is f(A).a.inherited
assert True is f(B).a.inherited
assert False is f(B).b.inherited
assert False is f(C).a.inherited
assert True is f(C).b.inherited
assert False is f(C).c.inherited
class TestAttributes:
"""
Tests for the `attrs`/`attr.s` class decorator.
"""
def test_sets_attrs(self):
"""
Sets the `__attrs_attrs__` class attribute with a list of `Attribute`s.
"""
@attr.s
class C:
x = attr.ib()
assert "x" == C.__attrs_attrs__[0].name
assert all(isinstance(a, Attribute) for a in C.__attrs_attrs__)
def test_empty(self):
"""
No attributes, no problems.
"""
@attr.s
class C3:
pass
assert "C3()" == repr(C3())
assert C3() == C3()
@given(attr=attrs_st, attr_name=sampled_from(Attribute.__slots__))
def test_immutable(self, attr, attr_name):
"""
Attribute instances are immutable.
"""
with pytest.raises(AttributeError):
setattr(attr, attr_name, 1)
@pytest.mark.parametrize(
"method_name", ["__repr__", "__eq__", "__hash__", "__init__"]
)
def test_adds_all_by_default(self, method_name):
"""
If no further arguments are supplied, all add_XXX functions except
add_hash are applied. __hash__ is set to None.
"""
# Set the method name to a sentinel and check whether it has been
# overwritten afterwards.
sentinel = object()
class C:
x = attr.ib()
setattr(C, method_name, sentinel)
C = attr.s(C)
meth = getattr(C, method_name)
assert sentinel != meth
if method_name == "__hash__":
assert meth is None
@pytest.mark.parametrize(
("arg_name", "method_name"),
[
("repr", "__repr__"),
("eq", "__eq__"),
("order", "__le__"),
("unsafe_hash", "__hash__"),
("init", "__init__"),
],
)
def test_respects_add_arguments(self, arg_name, method_name):
"""
If a certain `XXX` is `False`, `__XXX__` is not added to the class.
"""
# Set the method name to a sentinel and check whether it has been
# overwritten afterwards.
sentinel = object()
am_args = {
"repr": True,
"eq": True,
"order": True,
"unsafe_hash": True,
"init": True,
}
am_args[arg_name] = False
if arg_name == "eq":
am_args["order"] = False
class C:
x = attr.ib()
setattr(C, method_name, sentinel)
C = attr.s(**am_args)(C)
assert sentinel == getattr(C, method_name)
@pytest.mark.parametrize("init", [True, False])
def test_respects_init_attrs_init(self, init):
"""
If init=False, adds __attrs_init__ to the class.
Otherwise, it does not.
"""
class C:
x = attr.ib()
C = attr.s(init=init)(C)
assert hasattr(C, "__attrs_init__") != init
@given(slots_outer=booleans(), slots_inner=booleans())
def test_repr_qualname(self, slots_outer, slots_inner):
"""
The name in repr is the __qualname__.
"""
@attr.s(slots=slots_outer)
class C:
@attr.s(slots=slots_inner)
class D:
pass
assert "C.D()" == repr(C.D())
assert "GC.D()" == repr(GC.D())
@given(slots_outer=booleans(), slots_inner=booleans())
def test_repr_fake_qualname(self, slots_outer, slots_inner):
"""
Setting repr_ns overrides a potentially guessed namespace.
"""
with pytest.deprecated_call(match="The `repr_ns` argument"):
@attr.s(slots=slots_outer)
class C:
@attr.s(repr_ns="C", slots=slots_inner)
class D:
pass
assert "C.D()" == repr(C.D())
@given(slots_outer=booleans(), slots_inner=booleans())
def test_name_not_overridden(self, slots_outer, slots_inner):
"""
__name__ is different from __qualname__.
"""
@attr.s(slots=slots_outer)
class C:
@attr.s(slots=slots_inner)
class D:
pass
assert C.D.__name__ == "D"
assert C.D.__qualname__ == C.__qualname__ + ".D"
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_init(self):
"""
Verify that __attrs_pre_init__ gets called if defined.
"""
@attr.s
class C:
def __attrs_pre_init__(self2):
self2.z = 30
c = C()
assert 30 == getattr(c, "z", None)
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_init_args(self):
"""
Verify that __attrs_pre_init__ gets called with extra args if defined.
"""
@attr.s
class C:
x = attr.ib()
def __attrs_pre_init__(self2, x):
self2.z = x + 1
c = C(x=10)
assert 11 == getattr(c, "z", None)
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_init_kwargs(self):
"""
Verify that __attrs_pre_init__ gets called with extra args and kwargs
if defined.
"""
@attr.s
class C:
x = attr.ib()
y = attr.field(kw_only=True)
def __attrs_pre_init__(self2, x, y):
self2.z = x + y + 1
c = C(10, y=11)
assert 22 == getattr(c, "z", None)
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_init_kwargs_only(self):
"""
Verify that __attrs_pre_init__ gets called with extra kwargs only if
defined.
"""
@attr.s
class C:
y = attr.field(kw_only=True)
def __attrs_pre_init__(self2, y):
self2.z = y + 1
c = C(y=11)
assert 12 == getattr(c, "z", None)
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_init_kw_only_work_with_defaults(self):
"""
Default values together with kw_only don't break __attrs__pre_init__.
"""
val = None
@attr.define
class KWOnlyAndDefault:
kw_and_default: int = attr.field(kw_only=True, default=3)
def __attrs_pre_init__(self, *, kw_and_default):
nonlocal val
val = kw_and_default
inst = KWOnlyAndDefault()
assert 3 == val == inst.kw_and_default
@pytest.mark.usefixtures("with_and_without_validation")
def test_post_init(self):
"""
Verify that __attrs_post_init__ gets called if defined.
"""
@attr.s
class C:
x = attr.ib()
y = attr.ib()
def __attrs_post_init__(self2):
self2.z = self2.x + self2.y
c = C(x=10, y=20)
assert 30 == getattr(c, "z", None)
@pytest.mark.usefixtures("with_and_without_validation")
def test_pre_post_init_order(self):
"""
Verify that __attrs_post_init__ gets called if defined.
"""
@attr.s
class C:
x = attr.ib()
def __attrs_pre_init__(self2):
self2.z = 30
def __attrs_post_init__(self2):
self2.z += self2.x
c = C(x=10)
assert 40 == getattr(c, "z", None)
def test_types(self):
"""
Sets the `Attribute.type` attr from type argument.
"""
@attr.s
class C:
x = attr.ib(type=int)
y = attr.ib(type=str)
z = attr.ib()
assert int is fields(C).x.type
assert str is fields(C).y.type
assert None is fields(C).z.type
def test_clean_class(self, slots):
"""
Attribute definitions do not appear on the class body after @attr.s.
"""
@attr.s(slots=slots)
class C:
x = attr.ib()
x = getattr(C, "x", None)
assert not isinstance(x, _CountingAttr)
def test_factory_sugar(self):
"""
Passing factory=f is syntactic sugar for passing default=Factory(f).
"""
@attr.s
class C:
x = attr.ib(factory=list)
assert Factory(list) == attr.fields(C).x.default
def test_sugar_factory_mutex(self):
"""
Passing both default and factory raises ValueError.
"""
with pytest.raises(ValueError, match="mutually exclusive"):
@attr.s
class C:
x = attr.ib(factory=list, default=Factory(list))
def test_sugar_callable(self):
"""
Factory has to be a callable to prevent people from passing Factory
into it.
"""
with pytest.raises(ValueError, match="must be a callable"):
@attr.s
class C:
x = attr.ib(factory=Factory(list))
def test_inherited_does_not_affect_hashing_and_equality(self):
"""
Whether or not an Attribute has been inherited doesn't affect how it's
hashed and compared.
"""
@attr.s
class BaseClass:
x = attr.ib()
@attr.s
class SubClass(BaseClass):
pass
ba = attr.fields(BaseClass)[0]
sa = attr.fields(SubClass)[0]
assert ba == sa
assert hash(ba) == hash(sa)
class TestKeywordOnlyAttributes:
"""
Tests for keyword-only attributes.
"""
def test_adds_keyword_only_arguments(self):
"""
Attributes can be added as keyword-only.
"""
@attr.s
class C:
a = attr.ib()
b = attr.ib(default=2, kw_only=True)
c = attr.ib(kw_only=True)
d = attr.ib(default=attr.Factory(lambda: 4), kw_only=True)
c = C(1, c=3)
assert c.a == 1
assert c.b == 2
assert c.c == 3
assert c.d == 4
def test_ignores_kw_only_when_init_is_false(self):
"""
Specifying ``kw_only=True`` when ``init=False`` is essentially a no-op.
"""
@attr.s
class C:
x = attr.ib(init=False, default=0, kw_only=True)
y = attr.ib()
c = C(1)
assert c.x == 0
assert c.y == 1
def test_keyword_only_attributes_presence(self):
"""
Raises `TypeError` when keyword-only arguments are
not specified.
"""
@attr.s
class C:
x = attr.ib(kw_only=True)
with pytest.raises(TypeError) as e:
C()
assert (
"missing 1 required keyword-only argument: 'x'"
) in e.value.args[0]
def test_keyword_only_attributes_unexpected(self):
"""
Raises `TypeError` when unexpected keyword argument passed.
"""
@attr.s
class C:
x = attr.ib(kw_only=True)
with pytest.raises(TypeError) as e:
C(x=5, y=10)
assert "got an unexpected keyword argument 'y'" in e.value.args[0]
def test_keyword_only_attributes_can_come_in_any_order(self):
"""
Mandatory vs non-mandatory attr order only matters when they are part
of the __init__ signature and when they aren't kw_only (which are
moved to the end and can be mandatory or non-mandatory in any order,
as they will be specified as keyword args anyway).
"""
@attr.s
class C:
a = attr.ib(kw_only=True)
b = attr.ib(kw_only=True, default="b")
c = attr.ib(kw_only=True)
d = attr.ib()
e = attr.ib(default="e")
f = attr.ib(kw_only=True)
g = attr.ib(kw_only=True, default="g")
h = attr.ib(kw_only=True)
i = attr.ib(init=False)
c = C("d", a="a", c="c", f="f", h="h")
assert c.a == "a"
assert c.b == "b"
assert c.c == "c"
assert c.d == "d"
assert c.e == "e"
assert c.f == "f"
assert c.g == "g"
assert c.h == "h"
def test_keyword_only_attributes_allow_subclassing(self):
"""
Subclass can define keyword-only attributed without defaults,
when the base class has attributes with defaults.
"""
@attr.s
class Base:
x = attr.ib(default=0)
@attr.s
class C(Base):
y = attr.ib(kw_only=True)
c = C(y=1)
assert c.x == 0
assert c.y == 1
def test_keyword_only_class_level(self):
"""
`kw_only` can be provided at the attr.s level, converting all
attributes to `kw_only.`
"""
@attr.s(kw_only=True)
class C:
x = attr.ib()
y = attr.ib(kw_only=True)
with pytest.raises(TypeError):
C(0, y=1)
c = C(x=0, y=1)
assert c.x == 0
assert c.y == 1
def test_keyword_only_class_level_subclassing(self):
"""
Subclass `kw_only` propagates to attrs inherited from the base,
allowing non-default following default.
"""
@attr.s
class Base:
x = attr.ib(default=0)
@attr.s(kw_only=True)
class C(Base):
y = attr.ib()
with pytest.raises(TypeError):
C(1)
c = C(x=0, y=1)
assert c.x == 0
assert c.y == 1
def test_init_false_attribute_after_keyword_attribute(self):
"""
A positional attribute cannot follow a `kw_only` attribute,
but an `init=False` attribute can because it won't appear
in `__init__`
"""
@attr.s
class KwArgBeforeInitFalse:
kwarg = attr.ib(kw_only=True)
non_init_function_default = attr.ib(init=False)
non_init_keyword_default = attr.ib(
init=False, default="default-by-keyword"
)
@non_init_function_default.default
def _init_to_init(self):
return self.kwarg + "b"
c = KwArgBeforeInitFalse(kwarg="a")
assert c.kwarg == "a"
assert c.non_init_function_default == "ab"
assert c.non_init_keyword_default == "default-by-keyword"
def test_init_false_attribute_after_keyword_attribute_with_inheritance(
self,
):
"""
A positional attribute cannot follow a `kw_only` attribute,
but an `init=False` attribute can because it won't appear
in `__init__`. This test checks that we allow this
even when the `kw_only` attribute appears in a parent class
"""
@attr.s
class KwArgBeforeInitFalseParent:
kwarg = attr.ib(kw_only=True)
@attr.s
class KwArgBeforeInitFalseChild(KwArgBeforeInitFalseParent):
non_init_function_default = attr.ib(init=False)
non_init_keyword_default = attr.ib(
init=False, default="default-by-keyword"
)
@non_init_function_default.default
def _init_to_init(self):
return self.kwarg + "b"
c = KwArgBeforeInitFalseChild(kwarg="a")
assert c.kwarg == "a"
assert c.non_init_function_default == "ab"
assert c.non_init_keyword_default == "default-by-keyword"
@attr.s
class GC:
@attr.s
class D:
pass
class TestMakeClass:
"""
Tests for `make_class`.
"""
@pytest.mark.parametrize("ls", [list, tuple])
def test_simple(self, ls):
"""
Passing a list of strings creates attributes with default args.
"""
C1 = make_class("C1", ls(["a", "b"]))
@attr.s
class C2:
a = attr.ib()
b = attr.ib()
assert C1.__attrs_attrs__ == C2.__attrs_attrs__
def test_dict(self):
"""
Passing a dict of name: _CountingAttr creates an equivalent class.
"""
C1 = make_class(
"C1", {"a": attr.ib(default=42), "b": attr.ib(default=None)}
)
@attr.s
class C2:
a = attr.ib(default=42)
b = attr.ib(default=None)
assert C1.__attrs_attrs__ == C2.__attrs_attrs__
def test_attr_args(self):
"""
attributes_arguments are passed to attributes
"""
C = make_class("C", ["x"], repr=False)
assert repr(C(1)).startswith("<tests.test_make.C object at 0x")
def test_catches_wrong_attrs_type(self):
"""
Raise `TypeError` if an invalid type for attrs is passed.
"""
with pytest.raises(TypeError) as e:
make_class("C", object())
assert ("attrs argument must be a dict or a list.",) == e.value.args
def test_bases(self):
"""
Parameter bases default to (object,) and subclasses correctly
"""
class D:
pass
cls = make_class("C", {})
assert cls.__mro__[-1] is object
cls = make_class("C", {}, bases=(D,))
assert D in cls.__mro__
assert isinstance(cls(), D)
def test_additional_class_body(self):
"""
Additional class_body is added to newly created class.
"""
def echo_func(cls, *args):
return args
cls = make_class("C", {}, class_body={"echo": classmethod(echo_func)})
assert ("a", "b") == cls.echo("a", "b")
def test_clean_class(self, slots):
"""
Attribute definitions do not appear on the class body.
"""
C = make_class("C", ["x"], slots=slots)
x = getattr(C, "x", None)
assert not isinstance(x, _CountingAttr)
def test_missing_sys_getframe(self, monkeypatch):
"""
`make_class()` does not fail when `sys._getframe()` is not available.
"""
monkeypatch.delattr(sys, "_getframe")
C = make_class("C", ["x"])
assert 1 == len(C.__attrs_attrs__)
def test_make_class_ordered(self):
"""
If `make_class()` is passed ordered attrs, their order is respected
instead of the counter.
"""
b = attr.ib(default=2)
a = attr.ib(default=1)
C = attr.make_class("C", {"a": a, "b": b})
assert "C(a=1, b=2)" == repr(C())
def test_generic_dynamic_class(self):
"""
make_class can create generic dynamic classes.
https://github.com/python-attrs/attrs/issues/756
https://bugs.python.org/issue33188
"""
from types import new_class
from typing import Generic, TypeVar
MyTypeVar = TypeVar("MyTypeVar")
MyParent = new_class("MyParent", (Generic[MyTypeVar],), {})
attr.make_class("test", {"id": attr.ib(type=str)}, (MyParent[int],))
def test_annotations(self):
"""
make_class fills the __annotations__ dict for attributes with a known
type.
"""
a = attr.ib(type=bool)
b = attr.ib(
type=None
) # Won't be added to ann. b/c of unfavorable default
c = attr.ib()
C = attr.make_class("C", {"a": a, "b": b, "c": c})
C = attr.resolve_types(C)
assert {"a": bool} == C.__annotations__
def test_annotations_resolve(self):
"""
resolve_types() resolves the annotations added by make_class().
"""
a = attr.ib(type="bool")
C = attr.make_class("C", {"a": a})
C = attr.resolve_types(C)
assert attr.fields(C).a.type is bool
assert {"a": "bool"} == C.__annotations__
class TestFields:
"""
Tests for `fields`.
"""
@given(simple_classes())
def test_instance(self, C):
"""
Raises `TypeError` on non-classes.
"""
with pytest.raises(TypeError) as e:
fields(C())
assert "Passed object must be a class." == e.value.args[0]
def test_handler_non_attrs_class(self):
"""
Raises `ValueError` if passed a non-*attrs* instance.
"""
with pytest.raises(NotAnAttrsClassError) as e:
fields(object)
assert (
f"{object!r} is not an attrs-decorated class."
) == e.value.args[0]
def test_handler_non_attrs_generic_class(self):
"""
Raises `ValueError` if passed a non-*attrs* generic class.
"""
T = TypeVar("T")
class B(Generic[T]):
pass
with pytest.raises(NotAnAttrsClassError) as e:
fields(B[str])
assert (
f"{B[str]!r} is not an attrs-decorated class."
) == e.value.args[0]
@given(simple_classes())
def test_fields(self, C):
"""
Returns a list of `Attribute`a.
"""
assert all(isinstance(a, Attribute) for a in fields(C))
@given(simple_classes())
def test_fields_properties(self, C):
"""
Fields returns a tuple with properties.
"""
for attribute in fields(C):
assert getattr(fields(C), attribute.name) is attribute
def test_generics(self):
"""
Fields work with generic classes.
"""
T = TypeVar("T")
@attr.define
class A(Generic[T]):
a: T
assert len(fields(A)) == 1
assert fields(A).a.name == "a"
assert fields(A).a.default is attr.NOTHING
assert len(fields(A[str])) == 1
assert fields(A[str]).a.name == "a"
assert fields(A[str]).a.default is attr.NOTHING
class TestFieldsDict:
"""
Tests for `fields_dict`.
"""
@given(simple_classes())
def test_instance(self, C):
"""
Raises `TypeError` on non-classes.
"""
with pytest.raises(TypeError) as e:
fields_dict(C())
assert "Passed object must be a class." == e.value.args[0]
def test_handler_non_attrs_class(self):
"""
Raises `ValueError` if passed a non-*attrs* instance.
"""
with pytest.raises(NotAnAttrsClassError) as e:
fields_dict(object)
assert (
f"{object!r} is not an attrs-decorated class."
) == e.value.args[0]
@given(simple_classes())
def test_fields_dict(self, C):
"""
Returns an ordered dict of ``{attribute_name: Attribute}``.
"""
d = fields_dict(C)
assert isinstance(d, dict)
assert list(fields(C)) == list(d.values())
assert [a.name for a in fields(C)] == list(d)
class TestConverter:
"""
Tests for attribute conversion.
"""
def test_converter(self):
"""
Return value of converter is used as the attribute's value.
"""
C = make_class(
"C", {"x": attr.ib(converter=lambda v: v + 1), "y": attr.ib()}
)
c = C(1, 2)
assert c.x == 2
assert c.y == 2
def test_converter_wrapped_takes_self(self):
"""
When wrapped and passed `takes_self`, the converter receives the
instance that's being initializes -- and the return value is used as
the field's value.
"""
def converter_with_self(v, self_):
return v * self_.y
@attr.define
class C:
x: int = attr.field(
converter=attr.Converter(converter_with_self, takes_self=True)
)
y = 42
assert 84 == C(2).x
def test_converter_wrapped_takes_field(self):
"""
When wrapped and passed `takes_field`, the converter receives the field
definition -- and the return value is used as the field's value.
"""
def converter_with_field(v, field):
assert isinstance(field, attr.Attribute)
return v * field.metadata["x"]
@attr.define
class C:
x: int = attr.field(
converter=attr.Converter(
converter_with_field, takes_field=True
),
metadata={"x": 42},
)
assert 84 == C(2).x
@given(integers(), booleans())
def test_convert_property(self, val, init):
"""
Property tests for attributes using converter.
"""
C = make_class(
"C",
{
"y": attr.ib(),
"x": attr.ib(
init=init, default=val, converter=lambda v: v + 1
),
},
)
c = C(2)
assert c.x == val + 1
assert c.y == 2
@given(integers(), booleans())
def test_converter_factory_property(self, val, init):
"""
Property tests for attributes with converter, and a factory default.
"""
C = make_class(
"C",
{
"y": attr.ib(),
"x": attr.ib(
init=init,
default=Factory(lambda: val),
converter=lambda v: v + 1,
),
},
)
c = C(2)
assert c.x == val + 1
assert c.y == 2
def test_convert_before_validate(self):
"""
Validation happens after conversion.
"""
def validator(inst, attr, val):
raise RuntimeError("foo")
C = make_class(
"C",
{
"x": attr.ib(validator=validator, converter=lambda v: 1 / 0),
"y": attr.ib(),
},
)
with pytest.raises(ZeroDivisionError):
C(1, 2)
def test_frozen(self):
"""
Converters circumvent immutability.
"""
C = make_class(
"C", {"x": attr.ib(converter=lambda v: int(v))}, frozen=True
)
C("1")
class TestValidate:
"""
Tests for `validate`.
"""
def test_success(self):
"""
If the validator succeeds, nothing gets raised.
"""
C = make_class(
"C", {"x": attr.ib(validator=lambda *a: None), "y": attr.ib()}
)
validate(C(1, 2))
def test_propagates(self):
"""
The exception of the validator is handed through.
"""
def raiser(_, __, value):
if value == 42:
raise FloatingPointError
C = make_class("C", {"x": attr.ib(validator=raiser)})
i = C(1)
i.x = 42
with pytest.raises(FloatingPointError):
validate(i)
def test_run_validators(self):
"""
Setting `_run_validators` to False prevents validators from running.
"""
_config._run_validators = False
obj = object()
def raiser(_, __, ___):
raise Exception(obj)
C = make_class("C", {"x": attr.ib(validator=raiser)})
c = C(1)
validate(c)
assert 1 == c.x
_config._run_validators = True
with pytest.raises(Exception):
validate(c)
with pytest.raises(Exception) as e:
C(1)
assert (obj,) == e.value.args
def test_multiple_validators(self):
"""
If a list is passed as a validator, all of its items are treated as one
and must pass.
"""
def v1(_, __, value):
if value == 23:
raise TypeError("omg")
def v2(_, __, value):
if value == 42:
raise ValueError("omg")
C = make_class("C", {"x": attr.ib(validator=[v1, v2])})
validate(C(1))
with pytest.raises(TypeError) as e:
C(23)
assert "omg" == e.value.args[0]
with pytest.raises(ValueError) as e:
C(42)
assert "omg" == e.value.args[0]
def test_multiple_empty(self):
"""
Empty list/tuple for validator is the same as None.
"""
C1 = make_class("C", {"x": attr.ib(validator=[])})
C2 = make_class("C", {"x": attr.ib(validator=None)})
assert inspect.getsource(C1.__init__) == inspect.getsource(C2.__init__)
# Hypothesis seems to cache values, so the lists of attributes come out
# unsorted.
sorted_lists_of_attrs = list_of_attrs.map(
lambda ln: sorted(ln, key=attrgetter("counter"))
)
class TestMetadata:
"""
Tests for metadata handling.
"""
@given(sorted_lists_of_attrs)
def test_metadata_present(self, list_of_attrs):
"""
Assert dictionaries are copied and present.
"""
C = make_class("C", dict(zip(gen_attr_names(), list_of_attrs)))
for hyp_attr, class_attr in zip(list_of_attrs, fields(C)):
if hyp_attr.metadata is None:
# The default is a singleton empty dict.
assert class_attr.metadata is not None
assert len(class_attr.metadata) == 0
else:
assert hyp_attr.metadata == class_attr.metadata
# Once more, just to assert getting items and iteration.
for k in class_attr.metadata:
assert hyp_attr.metadata[k] == class_attr.metadata[k]
assert hyp_attr.metadata.get(k) == class_attr.metadata.get(
k
)
@given(simple_classes(), text())
def test_metadata_immutability(self, C, string):
"""
The metadata dict should be best-effort immutable.
"""
for a in fields(C):
with pytest.raises(TypeError):
a.metadata[string] = string
with pytest.raises(AttributeError):
a.metadata.update({string: string})
with pytest.raises(AttributeError):
a.metadata.clear()
with pytest.raises(AttributeError):
a.metadata.setdefault(string, string)
for k in a.metadata:
# For some reason, MappingProxyType throws an IndexError for
# deletes on a large integer key.
with pytest.raises((TypeError, IndexError)):
del a.metadata[k]
with pytest.raises(AttributeError):
a.metadata.pop(k)
with pytest.raises(AttributeError):
a.metadata.popitem()
@given(lists(simple_attrs_without_metadata, min_size=2, max_size=5))
def test_empty_metadata_singleton(self, list_of_attrs):
"""
All empty metadata attributes share the same empty metadata dict.
"""
C = make_class("C", dict(zip(gen_attr_names(), list_of_attrs)))
for a in fields(C)[1:]:
assert a.metadata is fields(C)[0].metadata
@given(lists(simple_attrs_without_metadata, min_size=2, max_size=5))
def test_empty_countingattr_metadata_independent(self, list_of_attrs):
"""
All empty metadata attributes are independent before ``@attr.s``.
"""
for x, y in itertools.combinations(list_of_attrs, 2):
assert x.metadata is not y.metadata
@given(lists(simple_attrs_with_metadata(), min_size=2, max_size=5))
def test_not_none_metadata(self, list_of_attrs):
"""
Non-empty metadata attributes exist as fields after ``@attr.s``.
"""
C = make_class("C", dict(zip(gen_attr_names(), list_of_attrs)))
assert len(fields(C)) > 0
for cls_a, raw_a in zip(fields(C), list_of_attrs):
assert cls_a.metadata != {}
assert cls_a.metadata == raw_a.metadata
def test_metadata(self):
"""
If metadata that is not None is passed, it is used.
This is necessary for coverage because the previous test is
hypothesis-based.
"""
md = {}
a = attr.ib(metadata=md)
assert md is a.metadata
class TestClassBuilder:
"""
Tests for `_ClassBuilder`.
"""
def test_repr_str(self):
"""
Trying to add a `__str__` without having a `__repr__` raises a
ValueError.
"""
with pytest.raises(ValueError) as ei:
make_class("C", {}, repr=False, str=True)
assert (
"__str__ can only be generated if a __repr__ exists.",
) == ei.value.args
def test_repr(self):
"""
repr of builder itself makes sense.
"""
class C:
pass
b = _ClassBuilder(
C,
None,
True,
True,
False,
False,
False,
False,
False,
False,
True,
None,
False,
None,
)
assert "<_ClassBuilder(cls=C)>" == repr(b)
def test_returns_self(self):
"""
All methods return the builder for chaining.
"""
class C:
x = attr.ib()
b = _ClassBuilder(
C,
None,
True,
True,
False,
False,
False,
False,
False,
False,
True,
None,
False,
None,
)
cls = (
b.add_eq()
.add_order()
.add_hash()
.add_init()
.add_attrs_init()
.add_repr("ns")
.add_str()
.build_class()
)
assert "ns.C(x=1)" == repr(cls(1))
@pytest.mark.parametrize(
"meth_name",
[
"__init__",
"__hash__",
"__repr__",
"__str__",
"__eq__",
"__ne__",
"__lt__",
"__le__",
"__gt__",
"__ge__",
],
)
def test_attaches_meta_dunders(self, meth_name):
"""
Generated methods have correct __module__, __name__, and __qualname__
attributes.
"""
@attr.s(unsafe_hash=True, str=True)
class C:
def organic(self):
pass
@attr.s(unsafe_hash=True, str=True)
class D:
pass
meth_C = getattr(C, meth_name)
meth_D = getattr(D, meth_name)
assert meth_name == meth_C.__name__ == meth_D.__name__
assert C.organic.__module__ == meth_C.__module__ == meth_D.__module__
# This is assertion that would fail if a single __ne__ instance
# was reused across multiple _make_eq calls.
organic_prefix = C.organic.__qualname__.rsplit(".", 1)[0]
assert organic_prefix + "." + meth_name == meth_C.__qualname__
def test_handles_missing_meta_on_class(self):
"""
If the class hasn't a __module__ or __qualname__, the method hasn't
either.
"""
class C:
pass
b = _ClassBuilder(
C,
these=None,
slots=False,
frozen=False,
weakref_slot=True,
getstate_setstate=False,
auto_attribs=False,
is_exc=False,
kw_only=False,
cache_hash=False,
collect_by_mro=True,
on_setattr=None,
has_custom_setattr=False,
field_transformer=None,
)
b._cls = {} # no __module__; no __qualname__
def fake_meth(self):
pass
fake_meth.__module__ = "42"
fake_meth.__qualname__ = "23"
rv = b._add_method_dunders(fake_meth)
assert "42" == rv.__module__ == fake_meth.__module__
assert "23" == rv.__qualname__ == fake_meth.__qualname__
def test_weakref_setstate(self):
"""
__weakref__ is not set on in setstate because it's not writable in
slotted classes.
"""
@attr.s(slots=True)
class C:
__weakref__ = attr.ib(
init=False, hash=False, repr=False, eq=False, order=False
)
assert C() == copy.deepcopy(C())
def test_no_references_to_original(self):
"""
When subclassing a slotted class, there are no stray references to the
original class.
"""
@attr.s(slots=True)
class C:
pass
@attr.s(slots=True)
class C2(C):
pass
# The original C2 is in a reference cycle, so force a collect:
gc.collect()
assert [C2] == C.__subclasses__()
@pytest.mark.xfail(PY_3_14_PLUS, reason="Currently broken on nightly.")
def test_no_references_to_original_when_using_cached_property(self):
"""
When subclassing a slotted class and using cached property, there are
no stray references to the original class.
"""
@attr.s(slots=True)
class C:
pass
@attr.s(slots=True)
class C2(C):
@functools.cached_property
def value(self) -> int:
return 0
# The original C2 is in a reference cycle, so force a collect:
gc.collect()
assert [C2] == C.__subclasses__()
def _get_copy_kwargs(include_slots=True):
"""
Generate a list of compatible attr.s arguments for the `copy` tests.
"""
options = ["frozen", "unsafe_hash", "cache_hash"]
if include_slots:
options.extend(["slots", "weakref_slot"])
out_kwargs = []
for args in itertools.product([True, False], repeat=len(options)):
kwargs = dict(zip(options, args))
kwargs["unsafe_hash"] = kwargs["unsafe_hash"] or None
if kwargs["cache_hash"] and not (
kwargs["frozen"] or kwargs["unsafe_hash"]
):
continue
out_kwargs.append(kwargs)
return out_kwargs
@pytest.mark.parametrize("kwargs", _get_copy_kwargs())
def test_copy(self, kwargs):
"""
Ensure that an attrs class can be copied successfully.
"""
@attr.s(eq=True, **kwargs)
class C:
x = attr.ib()
a = C(1)
b = copy.deepcopy(a)
assert a == b
@pytest.mark.parametrize("kwargs", _get_copy_kwargs(include_slots=False))
def test_copy_custom_setstate(self, kwargs):
"""
Ensure that non-slots classes respect a custom __setstate__.
"""
@attr.s(eq=True, **kwargs)
class C:
x = attr.ib()
def __getstate__(self):
return self.__dict__
def __setstate__(self, state):
state["x"] *= 5
self.__dict__.update(state)
expected = C(25)
actual = copy.copy(C(5))
assert actual == expected
class TestInitAlias:
"""
Tests for Attribute alias handling.
"""
def test_default_and_specify(self):
"""
alias is present on the Attributes returned from attr.fields.
If left unspecified, it defaults to standard private-attribute
handling. If specified, it passes through the explicit alias.
"""
# alias is None by default on _CountingAttr
default_counting = attr.ib()
assert default_counting.alias is None
override_counting = attr.ib(alias="specified")
assert override_counting.alias == "specified"
@attr.s
class Cases:
public_default = attr.ib()
_private_default = attr.ib()
__dunder_default__ = attr.ib()
public_override = attr.ib(alias="public")
_private_override = attr.ib(alias="_private")
__dunder_override__ = attr.ib(alias="__dunder__")
cases = attr.fields_dict(Cases)
# Default applies private-name mangling logic
assert cases["public_default"].name == "public_default"
assert cases["public_default"].alias == "public_default"
assert cases["_private_default"].name == "_private_default"
assert cases["_private_default"].alias == "private_default"
assert cases["__dunder_default__"].name == "__dunder_default__"
assert cases["__dunder_default__"].alias == "dunder_default__"
# Override is passed through
assert cases["public_override"].name == "public_override"
assert cases["public_override"].alias == "public"
assert cases["_private_override"].name == "_private_override"
assert cases["_private_override"].alias == "_private"
assert cases["__dunder_override__"].name == "__dunder_override__"
assert cases["__dunder_override__"].alias == "__dunder__"
# And aliases are applied to the __init__ signature
example = Cases(
public_default=1,
private_default=2,
dunder_default__=3,
public=4,
_private=5,
__dunder__=6,
)
assert example.public_default == 1
assert example._private_default == 2
assert example.__dunder_default__ == 3
assert example.public_override == 4
assert example._private_override == 5
assert example.__dunder_override__ == 6
def test_evolve(self):
"""
attr.evolve uses Attribute.alias to determine parameter names.
"""
@attr.s
class EvolveCase:
_override = attr.ib(alias="_override")
__mangled = attr.ib()
__dunder__ = attr.ib()
org = EvolveCase(1, 2, 3)
# Previous behavior of evolve as broken for double-underscore
# passthrough, and would raise here due to mis-mapping the __dunder__
# alias
assert attr.evolve(org) == org
# evolve uses the alias to match __init__ signature
assert attr.evolve(
org,
_override=0,
) == EvolveCase(0, 2, 3)
# and properly passes through dunders and mangles
assert attr.evolve(
org,
EvolveCase__mangled=4,
dunder__=5,
) == EvolveCase(1, 4, 5)
class TestMakeOrder:
"""
Tests for _make_order().
"""
def test_subclasses_cannot_be_compared(self):
"""
Calling comparison methods on subclasses raises a TypeError.
We use the actual operation so we get an error raised.
"""
@attr.s
class A:
a = attr.ib()
@attr.s
class B(A):
pass
a = A(42)
b = B(42)
assert a <= a
assert a >= a
assert not a < a
assert not a > a
assert (
NotImplemented
== a.__lt__(b)
== a.__le__(b)
== a.__gt__(b)
== a.__ge__(b)
)
with pytest.raises(TypeError):
a <= b
with pytest.raises(TypeError):
a >= b
with pytest.raises(TypeError):
a < b
with pytest.raises(TypeError):
a > b
class TestDetermineAttrsEqOrder:
def test_default(self):
"""
If all are set to None, set both eq and order to the passed default.
"""
assert (42, 42) == _determine_attrs_eq_order(None, None, None, 42)
@pytest.mark.parametrize("eq", [True, False])
def test_order_mirrors_eq_by_default(self, eq):
"""
If order is None, it mirrors eq.
"""
assert (eq, eq) == _determine_attrs_eq_order(None, eq, None, True)
def test_order_without_eq(self):
"""
eq=False, order=True raises a meaningful ValueError.
"""
with pytest.raises(
ValueError, match="`order` can only be True if `eq` is True too."
):
_determine_attrs_eq_order(None, False, True, True)
@given(cmp=booleans(), eq=optional_bool, order=optional_bool)
def test_mix(self, cmp, eq, order):
"""
If cmp is not None, eq and order must be None and vice versa.
"""
assume(eq is not None or order is not None)
with pytest.raises(
ValueError, match="Don't mix `cmp` with `eq' and `order`."
):
_determine_attrs_eq_order(cmp, eq, order, True)
class TestDetermineAttribEqOrder:
def test_default(self):
"""
If all are set to None, set both eq and order to the passed default.
"""
assert (42, None, 42, None) == _determine_attrib_eq_order(
None, None, None, 42
)
def test_eq_callable_order_boolean(self):
"""
eq=callable or order=callable need to transformed into eq/eq_key
or order/order_key.
"""
assert (True, str.lower, False, None) == _determine_attrib_eq_order(
None, str.lower, False, True
)
def test_eq_callable_order_callable(self):
"""
eq=callable or order=callable need to transformed into eq/eq_key
or order/order_key.
"""
assert (True, str.lower, True, abs) == _determine_attrib_eq_order(
None, str.lower, abs, True
)
def test_eq_boolean_order_callable(self):
"""
eq=callable or order=callable need to transformed into eq/eq_key
or order/order_key.
"""
assert (True, None, True, str.lower) == _determine_attrib_eq_order(
None, True, str.lower, True
)
@pytest.mark.parametrize("eq", [True, False])
def test_order_mirrors_eq_by_default(self, eq):
"""
If order is None, it mirrors eq.
"""
assert (eq, None, eq, None) == _determine_attrib_eq_order(
None, eq, None, True
)
def test_order_without_eq(self):
"""
eq=False, order=True raises a meaningful ValueError.
"""
with pytest.raises(
ValueError, match="`order` can only be True if `eq` is True too."
):
_determine_attrib_eq_order(None, False, True, True)
@given(cmp=booleans(), eq=optional_bool, order=optional_bool)
def test_mix(self, cmp, eq, order):
"""
If cmp is not None, eq and order must be None and vice versa.
"""
assume(eq is not None or order is not None)
with pytest.raises(
ValueError, match="Don't mix `cmp` with `eq' and `order`."
):
_determine_attrib_eq_order(cmp, eq, order, True)
class TestDocs:
@pytest.mark.parametrize(
"meth_name",
[
"__init__",
"__repr__",
"__eq__",
"__ne__",
"__lt__",
"__le__",
"__gt__",
"__ge__",
],
)
def test_docs(self, meth_name):
"""
Tests the presence and correctness of the documentation
for the generated methods
"""
@attr.s
class A:
pass
if hasattr(A, "__qualname__"):
method = getattr(A, meth_name)
expected = f"Method generated by attrs for class {A.__qualname__}."
assert expected == method.__doc__
class BareC:
pass
class BareSlottedC:
__slots__ = ()
class TestAutoDetect:
@pytest.mark.parametrize("C", [BareC, BareSlottedC])
def test_determine_detects_non_presence_correctly(self, C):
"""
On an empty class, nothing should be detected.
"""
assert True is _determine_whether_to_implement(
C, None, True, ("__init__",)
)
assert True is _determine_whether_to_implement(
C, None, True, ("__repr__",)
)
assert True is _determine_whether_to_implement(
C, None, True, ("__eq__", "__ne__")
)
assert True is _determine_whether_to_implement(
C, None, True, ("__le__", "__lt__", "__ge__", "__gt__")
)
def test_make_all_by_default(self, slots, frozen):
"""
If nothing is there to be detected, imply init=True, repr=True,
unsafe_hash=None, eq=True, order=True.
"""
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
i = C(1)
o = object()
assert i.__init__ is not o.__init__
assert i.__repr__ is not o.__repr__
assert i.__eq__ is not o.__eq__
assert i.__ne__ is not o.__ne__
assert i.__le__ is not o.__le__
assert i.__lt__ is not o.__lt__
assert i.__ge__ is not o.__ge__
assert i.__gt__ is not o.__gt__
def test_detect_auto_init(self, slots, frozen):
"""
If auto_detect=True and an __init__ exists, don't write one.
"""
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class CI:
x = attr.ib()
def __init__(self):
object.__setattr__(self, "x", 42)
assert 42 == CI().x
def test_detect_auto_repr(self, slots, frozen):
"""
If auto_detect=True and an __repr__ exists, don't write one.
"""
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __repr__(self):
return "hi"
assert "hi" == repr(C(42))
def test_hash_uses_eq(self, slots, frozen):
"""
If eq is passed in, then __hash__ should use the eq callable
to generate the hash code.
"""
@attr.s(slots=slots, frozen=frozen, unsafe_hash=True)
class C:
x = attr.ib(eq=str)
@attr.s(slots=slots, frozen=frozen, unsafe_hash=True)
class D:
x = attr.ib()
# These hashes should be the same because 1 is turned into
# string before hashing.
assert hash(C("1")) == hash(C(1))
assert hash(D("1")) != hash(D(1))
def test_detect_auto_hash(self, slots, frozen):
"""
If auto_detect=True and an __hash__ exists, don't write one.
"""
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __hash__(self):
return 0xC0FFEE
assert 0xC0FFEE == hash(C(42))
def test_detect_auto_eq(self, slots, frozen):
"""
If auto_detect=True and an __eq__ or an __ne__, exist, don't write one.
"""
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __eq__(self, o):
raise ValueError("worked")
with pytest.raises(ValueError, match="worked"):
C(1) == C(1)
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class D:
x = attr.ib()
def __ne__(self, o):
raise ValueError("worked")
with pytest.raises(ValueError, match="worked"):
D(1) != D(1)
def test_detect_auto_order(self, slots, frozen):
"""
If auto_detect=True and an __ge__, __gt__, __le__, or and __lt__ exist,
don't write one.
It's surprisingly difficult to test this programmatically, so we do it
by hand.
"""
def assert_not_set(cls, ex, meth_name):
__tracebackhide__ = True
a = getattr(cls, meth_name)
if meth_name == ex:
assert a == 42
else:
assert a is getattr(object, meth_name)
def assert_none_set(cls, ex):
__tracebackhide__ = True
for m in ("le", "lt", "ge", "gt"):
assert_not_set(cls, ex, "__" + m + "__")
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class LE:
__le__ = 42
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class LT:
__lt__ = 42
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class GE:
__ge__ = 42
@attr.s(auto_detect=True, slots=slots, frozen=frozen)
class GT:
__gt__ = 42
assert_none_set(LE, "__le__")
assert_none_set(LT, "__lt__")
assert_none_set(GE, "__ge__")
assert_none_set(GT, "__gt__")
def test_override_init(self, slots, frozen):
"""
If init=True is passed, ignore __init__.
"""
@attr.s(init=True, auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __init__(self):
pytest.fail("should not be called")
assert C(1) == C(1)
def test_override_repr(self, slots, frozen):
"""
If repr=True is passed, ignore __repr__.
"""
@attr.s(repr=True, auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __repr__(self):
pytest.fail("should not be called")
assert "C(x=1)" == repr(C(1))
def test_override_hash(self, slots, frozen):
"""
If unsafe_hash=True is passed, ignore __hash__.
"""
@attr.s(unsafe_hash=True, auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __hash__(self):
pytest.fail("should not be called")
assert hash(C(1))
def test_override_eq(self, slots, frozen):
"""
If eq=True is passed, ignore __eq__ and __ne__.
"""
@attr.s(eq=True, auto_detect=True, slots=slots, frozen=frozen)
class C:
x = attr.ib()
def __eq__(self, o):
pytest.fail("should not be called")
def __ne__(self, o):
pytest.fail("should not be called")
assert C(1) == C(1)
@pytest.mark.parametrize(
("eq", "order", "cmp"),
[
(True, None, None),
(True, True, None),
(None, True, None),
(None, None, True),
],
)
def test_override_order(self, slots, frozen, eq, order, cmp):
"""
If order=True is passed, ignore __le__, __lt__, __gt__, __ge__.
eq=True and cmp=True both imply order=True so test it too.
"""
def meth(self, o):
pytest.fail("should not be called")
@attr.s(
cmp=cmp,
order=order,
eq=eq,
auto_detect=True,
slots=slots,
frozen=frozen,
)
class C:
x = attr.ib()
__le__ = __lt__ = __gt__ = __ge__ = meth
assert C(1) < C(2)
assert C(1) <= C(2)
assert C(2) > C(1)
assert C(2) >= C(1)
@pytest.mark.parametrize("first", [True, False])
def test_total_ordering(self, slots, first):
"""
functools.total_ordering works as expected if an order method and an eq
method are detected.
Ensure the order doesn't matter.
"""
class C:
x = attr.ib()
own_eq_called = attr.ib(default=False)
own_le_called = attr.ib(default=False)
def __eq__(self, o):
self.own_eq_called = True
return self.x == o.x
def __le__(self, o):
self.own_le_called = True
return self.x <= o.x
if first:
C = functools.total_ordering(
attr.s(auto_detect=True, slots=slots)(C)
)
else:
C = attr.s(auto_detect=True, slots=slots)(
functools.total_ordering(C)
)
c1, c2 = C(1), C(2)
assert c1 < c2
assert c1.own_le_called
c1, c2 = C(1), C(2)
assert c2 > c1
assert c2.own_le_called
c1, c2 = C(1), C(2)
assert c2 != c1
assert c1 == c1
assert c1.own_eq_called
def test_detects_setstate_getstate(self, slots):
"""
__getstate__ and __setstate__ are not overwritten if either is present.
"""
@attr.s(slots=slots, auto_detect=True)
class C:
def __getstate__(self):
return ("hi",)
assert getattr(object, "__setstate__", None) is getattr(
C, "__setstate__", None
)
@attr.s(slots=slots, auto_detect=True)
class C:
called = attr.ib(False)
def __setstate__(self, state):
self.called = True
i = C()
assert False is i.called
i.__setstate__(())
assert True is i.called
assert getattr(object, "__getstate__", None) is getattr(
C, "__getstate__", None
)
@pytest.mark.skipif(PY_3_10_PLUS, reason="Pre-3.10 only.")
def test_match_args_pre_310(self):
"""
__match_args__ is not created on Python versions older than 3.10.
"""
@attr.s
class C:
a = attr.ib()
assert None is getattr(C, "__match_args__", None)
@pytest.mark.skipif(
not PY_3_10_PLUS, reason="Structural pattern matching is 3.10+"
)
class TestMatchArgs:
"""
Tests for match_args and __match_args__ generation.
"""
def test_match_args(self):
"""
__match_args__ is created by default on Python 3.10.
"""
@attr.define
class C:
a = attr.field()
assert ("a",) == C.__match_args__
def test_explicit_match_args(self):
"""
A custom __match_args__ set is not overwritten.
"""
ma = ()
@attr.define
class C:
a = attr.field()
__match_args__ = ma
assert C(42).__match_args__ is ma
@pytest.mark.parametrize("match_args", [True, False])
def test_match_args_attr_set(self, match_args):
"""
__match_args__ is set depending on match_args.
"""
@attr.define(match_args=match_args)
class C:
a = attr.field()
if match_args:
assert hasattr(C, "__match_args__")
else:
assert not hasattr(C, "__match_args__")
def test_match_args_kw_only(self):
"""
kw_only classes don't generate __match_args__.
kw_only fields are not included in __match_args__.
"""
@attr.define
class C:
a = attr.field(kw_only=True)
b = attr.field()
assert C.__match_args__ == ("b",)
@attr.define(kw_only=True)
class C:
a = attr.field()
b = attr.field()
assert C.__match_args__ == ()
def test_match_args_argument(self):
"""
match_args being False with inheritance.
"""
@attr.define(match_args=False)
class X:
a = attr.field()
assert "__match_args__" not in X.__dict__
@attr.define(match_args=False)
class Y:
a = attr.field()
__match_args__ = ("b",)
assert Y.__match_args__ == ("b",)
@attr.define(match_args=False)
class Z(Y):
z = attr.field()
assert Z.__match_args__ == ("b",)
@attr.define
class A:
a = attr.field()
z = attr.field()
@attr.define(match_args=False)
class B(A):
b = attr.field()
assert B.__match_args__ == ("a", "z")
def test_make_class(self):
"""
match_args generation with make_class.
"""
C1 = make_class("C1", ["a", "b"])
assert ("a", "b") == C1.__match_args__
C1 = make_class("C1", ["a", "b"], match_args=False)
assert not hasattr(C1, "__match_args__")
C1 = make_class("C1", ["a", "b"], kw_only=True)
assert () == C1.__match_args__
C1 = make_class("C1", {"a": attr.ib(kw_only=True), "b": attr.ib()})
assert ("b",) == C1.__match_args__
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