niceSOFT/python3-attrs: Python Classes Without Boilerplate

tests/test_funcs.py
677 строк19 KB
Hynek Schlawack
Drop Python 3.5 (#988)
05 авг 2022, 10:48
05 авг 2022, 10:4808f8319
# 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
        )