Test Bakery

Let's suppose we have class Settings and bakery MyBakery:

# file example.py
from dataclasses import dataclass
from bakery import Bakery, Cake


@dataclass
class Settings:
    dsn: str


class MyBakery(Bakery):
    dsn: str = Cake("real dsn")
    settings: Settings = Cake(Settings, dsn=dsn)

Let's consider two approaches for bakery testing: framework agnostic and pytest related approaches.

Framework agnostic approach

You can override any bakery member by passing argument for it to bakery:

from .example import MyBakery


async def test_example_1_no_mocks() -> None:
    async with MyBakery(dsn="fake dsn"):  # <<< pass new dsn value
        assert MyBakery().dsn == "fake dsn"
        assert MyBakery().settings.dsn == "fake dsn"

No particular framework required for it. It just works as expected and out-of-the-box.
The only downside of this approach is that you can't pass new arguments if bakery's been already opened:

import pytest

from .example import MyBakery


async def test_example_1_cant_pass_after_open() -> None:
    await MyBakery.aopen()

    with pytest.raises(TypeError):
        async with MyBakery(dsn="fake dsn"):  # <<< passing new arguments after open is prohibited
            ...

    await MyBakery.aclose()

If for some reason you need to override bakery's member after opening, please use pytest related approach.

Pytest related approach

Fresh Bakery appreciate the usage of pytest framework: you can use bakery_mock fixture out-of-the-box.

Note

To use bakery_mock fixture you have to also install pytest-mock library (besides pytest itself):

$ pip install pytest-mock

Info

bakery_mock is a function-scoped fixture. There are also other fixtures with different fixture scopes:

• class_bakery_mock is a class-scoped fixture
• module_bakery_mock is a module-scoped fixture
• package_bakery_mock is a package-scoped fixture
• session_bakery_mock is a session-scoped fixture

Patch before bakery opened

Let's see how to use bakery_mock fixture to test your bakery.

# file test_example.py
from bakery import Cake
from bakery.testbakery import BakeryMock

from .example import MyBakery


async def test_example_1(bakery_mock: BakeryMock) -> None:
    bakery_mock.dsn = Cake("fake dsn")  # <<< patch dsn
    async with bakery_mock(MyBakery):  # <<< mock against MyBakery
        assert MyBakery().dsn == "fake dsn"
        assert MyBakery().settings.dsn == "fake dsn"

In this example we patch dsn attribute (of any bakery) and then bind bakery_mock with the real bakery MyBakery.

Note

Note that bacause of we patch dsn attribute BEFORE bakery opened, all depending cakes are also becoming patched. In the example above settings cake are also patched with fake dsn.

Patch after bakery opened

You could also patch attributes after bakery was opened. But you should realize that the cake patched is the only thing that will be patched.

# file test_example.py
from bakery import Cake
from bakery.testbakery import BakeryMock

from .example import MyBakery


async def test_example_2(bakery_mock: BakeryMock) -> None:
    await MyBakery.aopen()  # open bakery anywhere

    bakery_mock.dsn = Cake("fake dsn")
    async with bakery_mock(MyBakery):
        assert MyBakery().dsn == "fake dsn"  # patched
        assert MyBakery().settings.dsn == "real dsn"  # not patched

    await MyBakery.aclose()  # close anywhere

Note that unlike the test_example_1 example, in the test_example_2 we patch MyBakery bakery after the bakery is opened. It means the cake settings is already baked and its .dsn value is "real dsn".

Patch hand made cakes

Hand made cakes are also supported:

# file test_example.py
from bakery import Bakery, BakingMethod, Cake, hand_made
from bakery.testbakery import BakeryMock

from .example import MyBakery


async def test_example_3(bakery_mock: BakeryMock) -> None:
    bakery_mock.settings = hand_made(
        Cake(list),
        cake_baking_method=BakingMethod.BAKE_NO_BAKE,
    )
    async with bakery_mock(MyBakery):
        assert MyBakery().settings is list