notifications-api/tests/notifications_utils/test_serialised_model.py

import sys

import pytest

from notifications_utils.serialised_model import (
    SerialisedModel,
    SerialisedModelCollection,
)


def test_cant_be_instatiated_with_abstract_properties():
    class Custom(SerialisedModel):
        pass

    class CustomCollection(SerialisedModelCollection):
        pass

    with pytest.raises(TypeError) as e:
        SerialisedModel()

    if sys.version_info < (3, 9):
        assert str(e.value) == (
            "Can't instantiate abstract class SerialisedModel with abstract methods ALLOWED_PROPERTIES"
        )
    else:
        assert "Can't instantiate abstract class SerialisedModel with abstract method ALLOWED_PROPERTIES"

    with pytest.raises(TypeError) as e:
        Custom()

    if sys.version_info < (3, 9):
        assert str(e.value) == (
            "Can't instantiate abstract class Custom with abstract methods ALLOWED_PROPERTIES"
        )
    else:
        assert str(e.value) == (
            "Can't instantiate abstract class Custom without an implementation for abstract method 'ALLOWED_PROPERTIES'"
        )

    with pytest.raises(TypeError) as e:
        SerialisedModelCollection()

    if sys.version_info < (3, 9):
        assert str(e.value) == (
            "Can't instantiate abstract class SerialisedModelCollection with abstract methods model"
        )
    else:
        assert str(e.value).startswith(
            "Can't instantiate abstract class SerialisedModelCollection without an implementation"
        )

    with pytest.raises(TypeError) as e:
        CustomCollection()

    if sys.version_info < (3, 9):
        assert str(e.value) == (
            "Can't instantiate abstract class CustomCollection with abstract methods model"
        )
    else:
        assert str(e.value) == (
            "Can't instantiate abstract class CustomCollection without an implementation for abstract method 'model'"
        )


def test_looks_up_from_dict():
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = {"foo"}

    assert Custom({"foo": "bar"}).foo == "bar"


def test_cant_override_custom_property_from_dict():
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = {"foo"}

        @property
        def foo(self):
            return "bar"

    with pytest.raises(AttributeError) as e:
        assert Custom({"foo": "NOPE"}).foo == "bar"
    assert (
        str(e.value)
        == "property 'foo' of 'test_cant_override_custom_property_from_dict.<locals>.Custom' object has no setter"
    )


@pytest.mark.parametrize(
    "json_response",
    (
        {},
        {"foo": "bar"},  # Should still raise an exception
    ),
)
def test_model_raises_for_unknown_attributes(json_response):
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = set()

    model = Custom(json_response)

    assert model.ALLOWED_PROPERTIES == set()

    with pytest.raises(AttributeError) as e:
        model.foo

    assert str(e.value) == ("'Custom' object has no attribute 'foo'")


def test_model_raises_keyerror_if_item_missing_from_dict():
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = {"foo"}

    with pytest.raises(KeyError) as e:
        Custom({}).foo

    assert str(e.value) == "'foo'"


@pytest.mark.parametrize(
    "json_response",
    (
        {},
        {"foo": "bar"},  # Should be ignored
    ),
)
def test_model_doesnt_swallow_attribute_errors(json_response):
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = set()

        @property
        def foo(self):
            raise AttributeError("Something has gone wrong")

    with pytest.raises(AttributeError) as e:
        Custom(json_response).foo

    assert str(e.value) == "Something has gone wrong"


def test_dynamic_properties_are_introspectable():
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = {"foo", "bar", "baz"}

    instance = Custom({"foo": "", "bar": "", "baz": ""})

    assert dir(instance)[-3:] == ["bar", "baz", "foo"]


def test_empty_serialised_model_collection():
    class CustomCollection(SerialisedModelCollection):
        model = None

    instance = CustomCollection([])

    assert not instance
    assert len(instance) == 0


def test_serialised_model_collection_returns_models_from_list():
    class Custom(SerialisedModel):
        ALLOWED_PROPERTIES = {"x"}

    class CustomCollection(SerialisedModelCollection):
        model = Custom

    instance = CustomCollection(
        [
            {"x": "foo"},
            {"x": "bar"},
            {"x": "baz"},
        ]
    )

    assert instance
    assert len(instance) == 3

    assert instance[0].x == "foo"
    assert instance[1].x == "bar"
    assert instance[2].x == "baz"

    assert [item.x for item in instance] == [
        "foo",
        "bar",
        "baz",
    ]

    assert [type(item) for item in instance + [1, 2, 3]] == [
        Custom,
        Custom,
        Custom,
        int,
        int,
        int,
    ]

    instance_2 = CustomCollection(
        [
            {"x": "red"},
            {"x": "green"},
            {"x": "blue"},
        ]
    )

    assert [item.x for item in instance + instance_2] == [
        "foo",
        "bar",
        "baz",
        "red",
        "green",
        "blue",
    ]

    assert [item.x for item in instance_2 + instance] == [
        "red",
        "green",
        "blue",
        "foo",
        "bar",
        "baz",
    ]