如何在pytest中导入函数 [英] how to import function in pytest

问题描述

我正在尝试为名称中包含破折号的 Python 2.x 脚本可执行文件创建一个 pytest.我试图以通常的方式导入它，但我不知道如何让它与破折号一起工作.

I am trying to create a pytest for a Python 2.x script executable with dashes included in its name. I tried to import it the usual way but I can't figure out how to make it work with the dashes.

我的项目结构如下:

package
    -- tests
    -- bin 
    -- subpackage
        -- ...py

具体来说，我需要测试一个名为 master_disaster() 的函数，它存在于 bin/let-me-out 中(是的，-).let-me-out 是一个可执行的 .py 文件，我的文件夹没有 setup.py 文件或任何类似的文件.

Specifically, I need to test a function called master_disaster() which exists inside bin/let-me-out (yes with -). let-me-out is an executable .py file and my folder has no setup.py file or anything similar.

如何在我的测试中导入这个函数?我的测试将是一个简单的装置，用于检查时间:

How can I import this function inside my test? My test is going to be a simple fixture that checks the time with:

@pytest.fixture
def now():
    return timezone.now()

然后使用 now() 函数创建一个新文件，let-me-out 将在特定时间后删除该文件.

It then uses the now() function to create a new file which let-me-out will delete after a specific amount of time.

推荐答案

首先，破折号使 let-me-out 字成为 Python 中的无效标识符.要解决它，您必须调用 imp (Python 2.7)或 importlib (Python 3.5+) 机器.

First of all, dashes make let-me-out word to an invalid identifier in Python. To work around it, you have to invoke the imp (Python 2.7) or importlib (Python 3.5+) machinery.

以下是导入具有限定名称 let_me_out、但使用 bin/let-me-out 作为源文件的新模块的示例:

Here is an example of importing a new module having a qualified name let_me_out, but using bin/let-me-out as source file:

import importlib


def test_master_disaster():
    loader = importlib.machinery.SourceFileLoader('let_me_out', 'bin/let-me-out')
    spec = importlib.util.spec_from_loader(loader.name, loader)
    let_me_out = importlib.util.module_from_spec(spec)
    loader.exec_module(let_me_out)
    # this is only a stub, to show an example of calling the master_disaster function
    assert let_me_out.master_disaster() == 'spam'

您可以将此代码提取到夹具中以使其可重用:

You can extract this code into a fixture to make it reusable:

import importlib
import pytest


@pytest.fixture(scope='session')
def let_me_out():
    loader = importlib.machinery.SourceFileLoader('let_me_out', 'bin/let-me-out')
    spec = importlib.util.spec_from_loader(loader.name, loader)
    let_me_out = importlib.util.module_from_spec(spec)
    loader.exec_module(let_me_out)
    return let_me_out


def test_master_disaster(let_me_out):
    assert let_me_out.master_disaster() == 'spam'

Python 2.7

Python 2.7 使事情变得更简单:

Python 2.7

Things are even easier with Python 2.7:

import imp
import pytest


@pytest.fixture(scope='session')
def let_me_out():
    return imp.load_source('let_me_out', 'bin/let-me-out')


def test_master_disaster(let_me_out):
    assert let_me_out.master_disaster() == 'spam'

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