如何模拟导入的函数？

Question

我尝试了多种方法，但无法得到我想要的结果。似乎很多问题都使用了整个 @patch 装饰器的不同类型的模拟，但我一直在使用这个更简化的版本。我只是不知道如何模拟一个函数，特别是 scan_all

主课

from databaseClass import scan_all
class JobsDB:
    def __init__(self, jobs_table):
        self.jobs_table = jobs_table

    async def get_all_jobs(self, include_executions=False):
        response = await scan_all(self.jobs_table)
        if include_executions:
            return [JobWithExecutions(**item) for item in response]
        return [Job(**item) for item in response]

数据库类

async def scan_all(table, **kwargs):
    response = await table.scan(**kwargs)
    items = response['Items']

    while 'LastEvaluatedKey' in response:
        response = await table.scan(**kwargs, ExclusiveStartKey=response['LastEvaluatedKey'])
        items = items + response['Items']

    return items

测试班

import pytest

from unittest.mock import AsyncMock, MagicMock

from db import JobsDB, Job

@pytest.fixture
def mock_scan_all():
    return AsyncMock()


@pytest.fixture
def jobs_table():
    return AsyncMock()



@pytest.fixture
def jobs_db():
    return JobsDB(AsyncMock())


@pytest.fixture
def job():
    return Job(
        id='1839e18a-898b-42d1-8747-9b5495dbb0a6',
        status='PENDING',
        description='Test',
        start_date='2024-01-22T13:00:00.000Z',
        end_date='2024-01-22T14:00:00.000Z',


@pytest.mark.database
@pytest.mark.asyncio
async def test_get_all_jobs(jobs_db, jobs_table, mock_scan_all, job):

    # This used a mock_scan_all fixture in the parameters
    mock_scan_all.return_value = [vars(job)]
    jobs_table.scan_all = mock_scan_all

    # Call the get_all_jobs method
    result = await jobs_db.get_all_jobs()

    # jobs_db.scan_all.assert_called_once_with(jobs_db.jobs_table)

    # Assert that the result is a list containing the expected Job object
    assert result == [job]

我尝试过的：

# Didn't work
    # jobs_db.jobs_table.scan_all = AsyncMock(return_value=[vars(job)])
# Didn't work
    # jobs_db.scan_all.return_value = [vars(job)]
# Didn't work
    # scan_all = AsyncMock()
    # scan_all.return_value = [vars(job)]
# Didn't work
    # mock = AsyncMock()
    # mock.scan_all.return_value = [vars(job)]
# Didn't work
    # mock_scan_all = AsyncMock()
    # mock_scan_all.return_value = [vars(job)]
    # jobs_table = MagicMock()
    # jobs_table.scan_all = mock_scan_all
# Didn't work
    # jobs_table.scan.return_value = {'Items': [vars(job) for job in jobs]}

我不断收到一条失败消息，指出右侧包含的项目多于左侧。左边什么都没有。

断言 [] == [作业]

我还尝试断言它是否被调用过一次并且总是返回 0 的结果。

Answer 1

添加这个似乎给了我结果并解决了所有问题。

@pytest.fixture
def mock_scan_all():
    with patch('module.jobs_db.scan_all') as mock:
        yield mock


async def test_get_all_jobs(jobs_db, jobs_table, mock_scan_all, job):
    mock_scan_all.return_value = [job.dict()]

    result = await jobs_db.get_all_jobs(include_executions=False)

    assert result == [job]