blob: ee30944982d5ea2ce307ac638f7712081aac98a9 [file] [log] [blame]
"""
Tests for PEP-526 type annotations.
Python 3.6+ only.
"""
import types
import typing
import pytest
import attr
from attr.exceptions import UnannotatedAttributeError
class TestAnnotations:
"""
Tests for types derived from variable annotations (PEP-526).
"""
def test_basic_annotations(self):
"""
Sets the `Attribute.type` attr from basic type annotations.
"""
@attr.s
class C:
x: int = attr.ib()
y = attr.ib(type=str)
z = attr.ib()
assert int is attr.fields(C).x.type
assert str is attr.fields(C).y.type
assert None is attr.fields(C).z.type
def test_catches_basic_type_conflict(self):
"""
Raises ValueError if type is specified both ways.
"""
with pytest.raises(ValueError) as e:
@attr.s
class C:
x: int = attr.ib(type=int)
assert (
"Type annotation and type argument cannot both be present",
) == e.value.args
def test_typing_annotations(self):
"""
Sets the `Attribute.type` attr from typing annotations.
"""
@attr.s
class C:
x: typing.List[int] = attr.ib()
y = attr.ib(type=typing.Optional[str])
assert typing.List[int] is attr.fields(C).x.type
assert typing.Optional[str] is attr.fields(C).y.type
def test_only_attrs_annotations_collected(self):
"""
Annotations that aren't set to an attr.ib are ignored.
"""
@attr.s
class C:
x: typing.List[int] = attr.ib()
y: int
assert 1 == len(attr.fields(C))
@pytest.mark.parametrize("slots", [True, False])
def test_auto_attribs(self, slots):
"""
If *auto_attribs* is True, bare annotations are collected too.
Defaults work and class variables are ignored.
"""
@attr.s(auto_attribs=True, slots=slots)
class C:
cls_var: typing.ClassVar[int] = 23
a: int
x: typing.List[int] = attr.Factory(list)
y: int = 2
z: int = attr.ib(default=3)
foo: typing.Any = None
i = C(42)
assert "C(a=42, x=[], y=2, z=3, foo=None)" == repr(i)
attr_names = set(a.name for a in C.__attrs_attrs__)
assert "a" in attr_names # just double check that the set works
assert "cls_var" not in attr_names
assert int == attr.fields(C).a.type
assert attr.Factory(list) == attr.fields(C).x.default
assert typing.List[int] == attr.fields(C).x.type
assert int == attr.fields(C).y.type
assert 2 == attr.fields(C).y.default
assert int == attr.fields(C).z.type
assert typing.Any == attr.fields(C).foo.type
# Class body is clean.
if slots is False:
with pytest.raises(AttributeError):
C.y
assert 2 == i.y
else:
assert isinstance(C.y, types.MemberDescriptorType)
i.y = 23
assert 23 == i.y
@pytest.mark.parametrize("slots", [True, False])
def test_auto_attribs_unannotated(self, slots):
"""
Unannotated `attr.ib`s raise an error.
"""
with pytest.raises(UnannotatedAttributeError) as e:
@attr.s(slots=slots, auto_attribs=True)
class C:
v = attr.ib()
x: int
y = attr.ib()
z: str
assert (
"The following `attr.ib`s lack a type annotation: v, y.",
) == e.value.args