attrs/tests/test_funcs.py

678 lines
19 KiB
Python

# SPDX-License-Identifier: MIT
"""
Tests for `attr._funcs`.
"""
from collections import OrderedDict
import pytest
from hypothesis import assume, given
from hypothesis import strategies as st
import attr
from attr import asdict, assoc, astuple, evolve, fields, has
from attr._compat import Mapping, Sequence
from attr.exceptions import AttrsAttributeNotFoundError
from attr.validators import instance_of
from .strategies import nested_classes, simple_classes
MAPPING_TYPES = (dict, OrderedDict)
SEQUENCE_TYPES = (list, tuple)
@pytest.fixture(scope="session", name="C")
def _C():
"""
Return a simple but fully featured attrs class with an x and a y attribute.
"""
import attr
@attr.s
class C:
x = attr.ib()
y = attr.ib()
return C
class TestAsDict:
"""
Tests for `asdict`.
"""
@given(st.sampled_from(MAPPING_TYPES))
def test_shallow(self, C, dict_factory):
"""
Shallow asdict returns correct dict.
"""
assert {"x": 1, "y": 2} == asdict(
C(x=1, y=2), False, dict_factory=dict_factory
)
@given(st.sampled_from(MAPPING_TYPES))
def test_recurse(self, C, dict_class):
"""
Deep asdict returns correct dict.
"""
assert {"x": {"x": 1, "y": 2}, "y": {"x": 3, "y": 4}} == asdict(
C(C(1, 2), C(3, 4)), dict_factory=dict_class
)
def test_nested_lists(self, C):
"""
Test unstructuring deeply nested lists.
"""
inner = C(1, 2)
outer = C([[inner]], None)
assert {"x": [[{"x": 1, "y": 2}]], "y": None} == asdict(outer)
def test_nested_dicts(self, C):
"""
Test unstructuring deeply nested dictionaries.
"""
inner = C(1, 2)
outer = C({1: {2: inner}}, None)
assert {"x": {1: {2: {"x": 1, "y": 2}}}, "y": None} == asdict(outer)
@given(nested_classes, st.sampled_from(MAPPING_TYPES))
def test_recurse_property(self, cls, dict_class):
"""
Property tests for recursive asdict.
"""
obj = cls()
obj_dict = asdict(obj, dict_factory=dict_class)
def assert_proper_dict_class(obj, obj_dict):
assert isinstance(obj_dict, dict_class)
for field in fields(obj.__class__):
field_val = getattr(obj, field.name)
if has(field_val.__class__):
# This field holds a class, recurse the assertions.
assert_proper_dict_class(field_val, obj_dict[field.name])
elif isinstance(field_val, Sequence):
dict_val = obj_dict[field.name]
for item, item_dict in zip(field_val, dict_val):
if has(item.__class__):
assert_proper_dict_class(item, item_dict)
elif isinstance(field_val, Mapping):
# This field holds a dictionary.
assert isinstance(obj_dict[field.name], dict_class)
for key, val in field_val.items():
if has(val.__class__):
assert_proper_dict_class(
val, obj_dict[field.name][key]
)
assert_proper_dict_class(obj, obj_dict)
@given(st.sampled_from(MAPPING_TYPES))
def test_filter(self, C, dict_factory):
"""
Attributes that are supposed to be skipped are skipped.
"""
assert {"x": {"x": 1}} == asdict(
C(C(1, 2), C(3, 4)),
filter=lambda a, v: a.name != "y",
dict_factory=dict_factory,
)
@given(container=st.sampled_from(SEQUENCE_TYPES))
def test_lists_tuples(self, container, C):
"""
If recurse is True, also recurse into lists.
"""
assert {
"x": 1,
"y": [{"x": 2, "y": 3}, {"x": 4, "y": 5}, "a"],
} == asdict(C(1, container([C(2, 3), C(4, 5), "a"])))
@given(container=st.sampled_from(SEQUENCE_TYPES))
def test_lists_tuples_retain_type(self, container, C):
"""
If recurse and retain_collection_types are True, also recurse
into lists and do not convert them into list.
"""
assert {
"x": 1,
"y": container([{"x": 2, "y": 3}, {"x": 4, "y": 5}, "a"]),
} == asdict(
C(1, container([C(2, 3), C(4, 5), "a"])),
retain_collection_types=True,
)
@given(set_type=st.sampled_from((set, frozenset)))
def test_sets_no_retain(self, C, set_type):
"""
Set types are converted to lists if retain_collection_types=False.
"""
d = asdict(
C(1, set_type((1, 2, 3))),
retain_collection_types=False,
recurse=True,
)
assert {"x": 1, "y": [1, 2, 3]} == d
@given(st.sampled_from(MAPPING_TYPES))
def test_dicts(self, C, dict_factory):
"""
If recurse is True, also recurse into dicts.
"""
res = asdict(C(1, {"a": C(4, 5)}), dict_factory=dict_factory)
assert {"x": 1, "y": {"a": {"x": 4, "y": 5}}} == res
assert isinstance(res, dict_factory)
@given(simple_classes(private_attrs=False), st.sampled_from(MAPPING_TYPES))
def test_roundtrip(self, cls, dict_class):
"""
Test dumping to dicts and back for Hypothesis-generated classes.
Private attributes don't round-trip (the attribute name is different
than the initializer argument).
"""
instance = cls()
dict_instance = asdict(instance, dict_factory=dict_class)
assert isinstance(dict_instance, dict_class)
roundtrip_instance = cls(**dict_instance)
assert instance == roundtrip_instance
@given(simple_classes())
def test_asdict_preserve_order(self, cls):
"""
Field order should be preserved when dumping to an ordered_dict.
"""
instance = cls()
dict_instance = asdict(instance, dict_factory=dict)
assert [a.name for a in fields(cls)] == list(dict_instance.keys())
def test_retain_keys_are_tuples(self):
"""
retain_collect_types also retains keys.
"""
@attr.s
class A:
a = attr.ib()
instance = A({(1,): 1})
assert {"a": {(1,): 1}} == attr.asdict(
instance, retain_collection_types=True
)
def test_tuple_keys(self):
"""
If a key is collection type, retain_collection_types is False,
the key is serialized as a tuple.
See #646
"""
@attr.s
class A:
a = attr.ib()
instance = A({(1,): 1})
assert {"a": {(1,): 1}} == attr.asdict(instance)
class TestAsTuple:
"""
Tests for `astuple`.
"""
@given(st.sampled_from(SEQUENCE_TYPES))
def test_shallow(self, C, tuple_factory):
"""
Shallow astuple returns correct dict.
"""
assert tuple_factory([1, 2]) == astuple(
C(x=1, y=2), False, tuple_factory=tuple_factory
)
@given(st.sampled_from(SEQUENCE_TYPES))
def test_recurse(self, C, tuple_factory):
"""
Deep astuple returns correct tuple.
"""
assert tuple_factory(
[tuple_factory([1, 2]), tuple_factory([3, 4])]
) == astuple(C(C(1, 2), C(3, 4)), tuple_factory=tuple_factory)
@given(nested_classes, st.sampled_from(SEQUENCE_TYPES))
def test_recurse_property(self, cls, tuple_class):
"""
Property tests for recursive astuple.
"""
obj = cls()
obj_tuple = astuple(obj, tuple_factory=tuple_class)
def assert_proper_tuple_class(obj, obj_tuple):
assert isinstance(obj_tuple, tuple_class)
for index, field in enumerate(fields(obj.__class__)):
field_val = getattr(obj, field.name)
if has(field_val.__class__):
# This field holds a class, recurse the assertions.
assert_proper_tuple_class(field_val, obj_tuple[index])
assert_proper_tuple_class(obj, obj_tuple)
@given(nested_classes, st.sampled_from(SEQUENCE_TYPES))
def test_recurse_retain(self, cls, tuple_class):
"""
Property tests for asserting collection types are retained.
"""
obj = cls()
obj_tuple = astuple(
obj, tuple_factory=tuple_class, retain_collection_types=True
)
def assert_proper_col_class(obj, obj_tuple):
# Iterate over all attributes, and if they are lists or mappings
# in the original, assert they are the same class in the dumped.
for index, field in enumerate(fields(obj.__class__)):
field_val = getattr(obj, field.name)
if has(field_val.__class__):
# This field holds a class, recurse the assertions.
assert_proper_col_class(field_val, obj_tuple[index])
elif isinstance(field_val, (list, tuple)):
# This field holds a sequence of something.
expected_type = type(obj_tuple[index])
assert type(field_val) is expected_type
for obj_e, obj_tuple_e in zip(field_val, obj_tuple[index]):
if has(obj_e.__class__):
assert_proper_col_class(obj_e, obj_tuple_e)
elif isinstance(field_val, dict):
orig = field_val
tupled = obj_tuple[index]
assert type(orig) is type(tupled)
for obj_e, obj_tuple_e in zip(
orig.items(), tupled.items()
):
if has(obj_e[0].__class__): # Dict key
assert_proper_col_class(obj_e[0], obj_tuple_e[0])
if has(obj_e[1].__class__): # Dict value
assert_proper_col_class(obj_e[1], obj_tuple_e[1])
assert_proper_col_class(obj, obj_tuple)
@given(st.sampled_from(SEQUENCE_TYPES))
def test_filter(self, C, tuple_factory):
"""
Attributes that are supposed to be skipped are skipped.
"""
assert tuple_factory([tuple_factory([1])]) == astuple(
C(C(1, 2), C(3, 4)),
filter=lambda a, v: a.name != "y",
tuple_factory=tuple_factory,
)
@given(container=st.sampled_from(SEQUENCE_TYPES))
def test_lists_tuples(self, container, C):
"""
If recurse is True, also recurse into lists.
"""
assert (1, [(2, 3), (4, 5), "a"]) == astuple(
C(1, container([C(2, 3), C(4, 5), "a"]))
)
@given(st.sampled_from(SEQUENCE_TYPES))
def test_dicts(self, C, tuple_factory):
"""
If recurse is True, also recurse into dicts.
"""
res = astuple(C(1, {"a": C(4, 5)}), tuple_factory=tuple_factory)
assert tuple_factory([1, {"a": tuple_factory([4, 5])}]) == res
assert isinstance(res, tuple_factory)
@given(container=st.sampled_from(SEQUENCE_TYPES))
def test_lists_tuples_retain_type(self, container, C):
"""
If recurse and retain_collection_types are True, also recurse
into lists and do not convert them into list.
"""
assert (1, container([(2, 3), (4, 5), "a"])) == astuple(
C(1, container([C(2, 3), C(4, 5), "a"])),
retain_collection_types=True,
)
@given(container=st.sampled_from(MAPPING_TYPES))
def test_dicts_retain_type(self, container, C):
"""
If recurse and retain_collection_types are True, also recurse
into lists and do not convert them into list.
"""
assert (1, container({"a": (4, 5)})) == astuple(
C(1, container({"a": C(4, 5)})), retain_collection_types=True
)
@given(simple_classes(), st.sampled_from(SEQUENCE_TYPES))
def test_roundtrip(self, cls, tuple_class):
"""
Test dumping to tuple and back for Hypothesis-generated classes.
"""
instance = cls()
tuple_instance = astuple(instance, tuple_factory=tuple_class)
assert isinstance(tuple_instance, tuple_class)
roundtrip_instance = cls(*tuple_instance)
assert instance == roundtrip_instance
@given(set_type=st.sampled_from((set, frozenset)))
def test_sets_no_retain(self, C, set_type):
"""
Set types are converted to lists if retain_collection_types=False.
"""
d = astuple(
C(1, set_type((1, 2, 3))),
retain_collection_types=False,
recurse=True,
)
assert (1, [1, 2, 3]) == d
class TestHas:
"""
Tests for `has`.
"""
def test_positive(self, C):
"""
Returns `True` on decorated classes.
"""
assert has(C)
def test_positive_empty(self):
"""
Returns `True` on decorated classes even if there are no attributes.
"""
@attr.s
class D:
pass
assert has(D)
def test_negative(self):
"""
Returns `False` on non-decorated classes.
"""
assert not has(object)
class TestAssoc:
"""
Tests for `assoc`.
"""
@given(slots=st.booleans(), frozen=st.booleans())
def test_empty(self, slots, frozen):
"""
Empty classes without changes get copied.
"""
@attr.s(slots=slots, frozen=frozen)
class C:
pass
i1 = C()
with pytest.deprecated_call():
i2 = assoc(i1)
assert i1 is not i2
assert i1 == i2
@given(simple_classes())
def test_no_changes(self, C):
"""
No changes means a verbatim copy.
"""
i1 = C()
with pytest.deprecated_call():
i2 = assoc(i1)
assert i1 is not i2
assert i1 == i2
@given(simple_classes(), st.data())
def test_change(self, C, data):
"""
Changes work.
"""
# Take the first attribute, and change it.
assume(fields(C)) # Skip classes with no attributes.
field_names = [a.name for a in fields(C)]
original = C()
chosen_names = data.draw(st.sets(st.sampled_from(field_names)))
change_dict = {name: data.draw(st.integers()) for name in chosen_names}
with pytest.deprecated_call():
changed = assoc(original, **change_dict)
for k, v in change_dict.items():
assert getattr(changed, k) == v
@given(simple_classes())
def test_unknown(self, C):
"""
Wanting to change an unknown attribute raises an
AttrsAttributeNotFoundError.
"""
# No generated class will have a four letter attribute.
with pytest.raises(
AttrsAttributeNotFoundError
) as e, pytest.deprecated_call():
assoc(C(), aaaa=2)
assert (f"aaaa is not an attrs attribute on {C!r}.",) == e.value.args
def test_frozen(self):
"""
Works on frozen classes.
"""
@attr.s(frozen=True)
class C:
x = attr.ib()
y = attr.ib()
with pytest.deprecated_call():
assert C(3, 2) == assoc(C(1, 2), x=3)
def test_warning(self):
"""
DeprecationWarning points to the correct file.
"""
@attr.s
class C:
x = attr.ib()
with pytest.warns(DeprecationWarning) as wi:
assert C(2) == assoc(C(1), x=2)
assert __file__ == wi.list[0].filename
class TestEvolve:
"""
Tests for `evolve`.
"""
@given(slots=st.booleans(), frozen=st.booleans())
def test_empty(self, slots, frozen):
"""
Empty classes without changes get copied.
"""
@attr.s(slots=slots, frozen=frozen)
class C:
pass
i1 = C()
i2 = evolve(i1)
assert i1 is not i2
assert i1 == i2
@given(simple_classes())
def test_no_changes(self, C):
"""
No changes means a verbatim copy.
"""
i1 = C()
i2 = evolve(i1)
assert i1 is not i2
assert i1 == i2
@given(simple_classes(), st.data())
def test_change(self, C, data):
"""
Changes work.
"""
# Take the first attribute, and change it.
assume(fields(C)) # Skip classes with no attributes.
field_names = [a.name for a in fields(C)]
original = C()
chosen_names = data.draw(st.sets(st.sampled_from(field_names)))
# We pay special attention to private attributes, they should behave
# like in `__init__`.
change_dict = {
name.replace("_", ""): data.draw(st.integers())
for name in chosen_names
}
changed = evolve(original, **change_dict)
for name in chosen_names:
assert getattr(changed, name) == change_dict[name.replace("_", "")]
@given(simple_classes())
def test_unknown(self, C):
"""
Wanting to change an unknown attribute raises an
AttrsAttributeNotFoundError.
"""
# No generated class will have a four letter attribute.
with pytest.raises(TypeError) as e:
evolve(C(), aaaa=2)
if hasattr(C, "__attrs_init__"):
expected = (
"__attrs_init__() got an unexpected keyword argument 'aaaa'"
)
else:
expected = "__init__() got an unexpected keyword argument 'aaaa'"
assert e.value.args[0].endswith(expected)
def test_validator_failure(self):
"""
TypeError isn't swallowed when validation fails within evolve.
"""
@attr.s
class C:
a = attr.ib(validator=instance_of(int))
with pytest.raises(TypeError) as e:
evolve(C(a=1), a="some string")
m = e.value.args[0]
assert m.startswith("'a' must be <class 'int'>")
def test_private(self):
"""
evolve() acts as `__init__` with regards to private attributes.
"""
@attr.s
class C:
_a = attr.ib()
assert evolve(C(1), a=2)._a == 2
with pytest.raises(TypeError):
evolve(C(1), _a=2)
with pytest.raises(TypeError):
evolve(C(1), a=3, _a=2)
def test_non_init_attrs(self):
"""
evolve() handles `init=False` attributes.
"""
@attr.s
class C:
a = attr.ib()
b = attr.ib(init=False, default=0)
assert evolve(C(1), a=2).a == 2
def test_regression_attrs_classes(self):
"""
evolve() can evolve fields that are instances of attrs classes.
Regression test for #804
"""
@attr.s
class Cls1:
param1 = attr.ib()
@attr.s
class Cls2:
param2 = attr.ib()
obj2a = Cls2(param2="a")
obj2b = Cls2(param2="b")
obj1a = Cls1(param1=obj2a)
assert Cls1(param1=Cls2(param2="b")) == attr.evolve(
obj1a, param1=obj2b
)
def test_dicts(self):
"""
evolve() can replace an attrs class instance with a dict.
See #806
"""
@attr.s
class Cls1:
param1 = attr.ib()
@attr.s
class Cls2:
param2 = attr.ib()
obj2a = Cls2(param2="a")
obj2b = {"foo": 42, "param2": 42}
obj1a = Cls1(param1=obj2a)
assert Cls1({"foo": 42, "param2": 42}) == attr.evolve(
obj1a, param1=obj2b
)