attrs/tests/test_dunders.py

318 lines
7.7 KiB
Python

# -*- coding: utf-8 -*-
"""
Tests for dunder methods from `attrib._make`.
"""
from __future__ import absolute_import, division, print_function
import copy
import pytest
from . import simple_attr, simple_class
from attr._compat import PY26
from attr._make import (
Factory,
NOTHING,
_Nothing,
_add_init,
_add_repr,
attr,
make_class,
)
from attr.validators import instance_of
CmpC = simple_class(add_cmp=True)
ReprC = simple_class(add_repr=True)
HashC = simple_class(add_hash=True)
class InitC(object):
__attrs_attrs__ = [simple_attr("a"), simple_attr("b")]
InitC = _add_init(InitC)
class TestAddCmp(object):
"""
Tests for `_add_cmp`.
"""
def test_no_cmp(self):
"""
If `no_cmp` is set, ignore that attribute.
"""
C = make_class("C", {"a": attr(no_cmp=True), "b": attr()})
assert C(1, 2) == C(2, 2)
def test_equal(self):
"""
Equal objects are detected as equal.
"""
assert CmpC(1, 2) == CmpC(1, 2)
assert not (CmpC(1, 2) != CmpC(1, 2))
def test_unequal_same_class(self):
"""
Unequal objects of correct type are detected as unequal.
"""
assert CmpC(1, 2) != CmpC(2, 1)
assert not (CmpC(1, 2) == CmpC(2, 1))
def test_unequal_different_class(self):
"""
Unequal objects of differnt type are detected even if their attributes
match.
"""
class NotCmpC(object):
a = 1
b = 2
assert CmpC(1, 2) != NotCmpC()
assert not (CmpC(1, 2) == NotCmpC())
def test_lt(self):
"""
__lt__ compares objects as tuples of attribute values.
"""
for a, b in [
((1, 2), (2, 1)),
((1, 2), (1, 3)),
(("a", "b"), ("b", "a")),
]:
assert CmpC(*a) < CmpC(*b)
def test_lt_unordable(self):
"""
__lt__ returns NotImplemented if classes differ.
"""
assert NotImplemented == (CmpC(1, 2).__lt__(42))
def test_le(self):
"""
__le__ compares objects as tuples of attribute values.
"""
for a, b in [
((1, 2), (2, 1)),
((1, 2), (1, 3)),
((1, 1), (1, 1)),
(("a", "b"), ("b", "a")),
(("a", "b"), ("a", "b")),
]:
assert CmpC(*a) <= CmpC(*b)
def test_le_unordable(self):
"""
__le__ returns NotImplemented if classes differ.
"""
assert NotImplemented == (CmpC(1, 2).__le__(42))
def test_gt(self):
"""
__gt__ compares objects as tuples of attribute values.
"""
for a, b in [
((2, 1), (1, 2)),
((1, 3), (1, 2)),
(("b", "a"), ("a", "b")),
]:
assert CmpC(*a) > CmpC(*b)
def test_gt_unordable(self):
"""
__gt__ returns NotImplemented if classes differ.
"""
assert NotImplemented == (CmpC(1, 2).__gt__(42))
def test_ge(self):
"""
__ge__ compares objects as tuples of attribute values.
"""
for a, b in [
((2, 1), (1, 2)),
((1, 3), (1, 2)),
((1, 1), (1, 1)),
(("b", "a"), ("a", "b")),
(("a", "b"), ("a", "b")),
]:
assert CmpC(*a) >= CmpC(*b)
def test_ge_unordable(self):
"""
__ge__ returns NotImplemented if classes differ.
"""
assert NotImplemented == (CmpC(1, 2).__ge__(42))
class TestAddRepr(object):
"""
Tests for `_add_repr`.
"""
def test_no_repr(self):
"""
If `no_repr` is set, ignore that attribute.
"""
C = make_class("C", {"a": attr(no_repr=True), "b": attr()})
assert "C(b=2)" == repr(C(1, 2))
def test_repr(self):
"""
repr returns a sensible value.
"""
assert "C(a=1, b=2)" == repr(ReprC(1, 2))
def test_underscores(self):
"""
repr does not strip underscores.
"""
class C(object):
__attrs_attrs__ = [simple_attr("_x")]
C = _add_repr(C)
i = C()
i._x = 42
assert "C(_x=42)" == repr(i)
class TestAddHash(object):
"""
Tests for `_add_hash`.
"""
def test_no_hash(self):
"""
If `no_hash` is set, ignore that attribute.
"""
C = make_class("C", {"a": attr(no_hash=True), "b": attr()})
assert hash(C(1, 2)) == hash(C(2, 2))
def test_hash(self):
"""
__hash__ returns different hashes for different values.
"""
assert hash(HashC(1, 2)) != hash(HashC(1, 1))
class TestAddInit(object):
"""
Tests for `_add_init`.
"""
def test_no_init(self):
"""
If `no_init` is set, ignore that attribute.
"""
C = make_class("C", {"a": attr(no_init=True), "b": attr()})
with pytest.raises(TypeError) as e:
C(a=1, b=2)
msg = e.value if PY26 else e.value.args[0]
assert "__init__() got an unexpected keyword argument 'a'" == msg
def test_sets_attributes(self):
"""
The attributes are initialized using the passed keywords.
"""
obj = InitC(a=1, b=2)
assert 1 == obj.a
assert 2 == obj.b
def test_default(self):
"""
If a default value is present, it's used as fallback.
"""
class C(object):
__attrs_attrs__ = [
simple_attr(name="a", default=2),
simple_attr(name="b", default="hallo"),
simple_attr(name="c", default=None),
]
C = _add_init(C)
i = C()
assert 2 == i.a
assert "hallo" == i.b
assert None is i.c
def test_factory(self):
"""
If a default factory is present, it's used as fallback.
"""
class D(object):
pass
class C(object):
__attrs_attrs__ = [
simple_attr(name="a", default=Factory(list)),
simple_attr(name="b", default=Factory(D)),
]
C = _add_init(C)
i = C()
assert [] == i.a
assert isinstance(i.b, D)
def test_validator(self):
"""
If a validator is passed, call it with the Attribute and the argument.
"""
class VException(Exception):
pass
def raiser(*args):
raise VException(args)
C = make_class("C", {"a": attr("a", validator=raiser)})
with pytest.raises(VException) as e:
C(42)
assert ((C.a, 42,),) == e.value.args
def test_validator_others(self):
"""
Does not interfere when setting non-attrs attributes.
"""
C = make_class("C", {"a": attr("a", validator=instance_of(int))})
i = C(1)
i.b = "foo"
assert 1 == i.a
assert "foo" == i.b
def test_underscores(self):
"""
The argument names in `__init__` are without leading and trailing
underscores.
"""
class C(object):
__attrs_attrs__ = [simple_attr("_private")]
C = _add_init(C)
i = C(private=42)
assert 42 == i._private
class TestNothing(object):
"""
Tests for `_Nothing`.
"""
def test_copy(self):
"""
__copy__ returns the same object.
"""
n = _Nothing()
assert n is copy.copy(n)
def test_deepcopy(self):
"""
__deepcopy__ returns the same object.
"""
n = _Nothing()
assert n is copy.deepcopy(n)
def test_eq(self):
"""
All instances are equal.
"""
assert _Nothing() == _Nothing() == NOTHING
assert not (_Nothing() != _Nothing)