pytest doesn't run any tests and it is not clear why. I tried to use --debug but didn't get any valuable information. It is completely not clear how to debug this sort of issues with pytest. (Looks like some issue with pytest configuration / env variables / test names patterns?)

PYTEST不运行任何测试，原因尚不清楚。我试图使用--DEBUG，但没有得到任何有价值的信息。完全不清楚如何用PYTEST调试这类问题。(看起来像是关于pytest配置/环境变量/测试名称模式的一些问题？)

Example of test file:

测试文件示例：

import pytest

@pytest.mark.sanity
def test_me():
    """I'm a test."""

    assert True

But pytest doesn't run any test, why?

但是pytest不运行任何测试，为什么？

$ pytest
================================================== test session starts ===================================================
platform linux2 -- Python 2.7.12, pytest-3.1.3, py-1.4.34, pluggy-0.4.0
rootdir: /home/qawizard/pytest-hell, inifile:
plugins: xdist-1.15.0, timeout-1.2.0
collected 1 item s

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Exit: Done! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
============================================== no tests ran in 0.13 seconds ==============================================

To determine why tests are not running, these steps are useful:

要确定测试未运行的原因，以下步骤很有用：

1. Verify that all files with test cases have a 'test_' prefix.


2. Verify that all test case names also have a 'test_' prefix.


3. Verify that you have created pytest.ini file in the root directory.


4. Verify that you have __init__.py file in all directories/sub-directories of the project.

You need all tests to start with test_ but also you need to tell Pytest exact which files to look for:

您需要所有测试都以test_开头，但您还需要告诉Pytest确切要查找哪些文件：

# pytest.ini

[pytest]

DJANGO_SETTIONS_MODULE = myproject.settings
python_files = tests.py test_*.py

For me my class name didn't start with test.

对我来说，我的类名不是以test开头的。

my code was

我的代码是

class MainTest:
    ...

    def test_properties(self):
        ...

This wont work because pytest will assume this class shouldn't be included.
Changing to this did it for me.

这是行不通的，因为pytest会假定不应该包含这个类。换成这个对我来说是有好处的。

class TestMain:
    ...

    def test_properties(self):
        ...

For example, there is apples/apple.py as shown below:

例如，有苹果/apple.py，如下所示：

project
 |-pytest.ini
 └-apples
    |-__init__.py
    └-apple.py # Here

Then, there is apple(self) in Apple class in apples/apple.py as shown below:

然后，在Apple/apple.py中的Apple类中有Apple(Self)，如下所示：

# "apples/apple.py"

import pytest

class Apple:
    def apple(self):
        assert True

Now, with this pytest.ini below, apple(self) cannot be run because by default, Pytest can run the files test_*.py and *_test.py, the classes prefixed with Test and the functions prefixed with test instead of apple.py file, Apple class and apple(self) function according to python_files, python_classes and python_functions and by default, Pytest can run any folders like apples:

现在，有了下面的pyest.ini，Apple(Self)就不能运行了，因为默认情况下，Pytest可以运行文件test_*.py和*_test.py，以及以test为前缀的类和前缀为test的函数，而不是以apple.py文件、Apple类和Apple(Self)函数为前缀。默认情况下，Pytest可以运行任何文件夹，如Apple：

# "pytest.ini"

[pytest]

So, with this pytest.ini below, apple(self) can be run:

因此，使用下面的pyest.ini文件，可以运行Apple(Self)：

# "pytest.ini"

[pytest]
python_files = apple.py
python_classes = Apple
python_functions = apple

In addition, by default, you can run all the tests in apples/test_1.py, apples/oranges/test_2.py, bananas/test_1.py and banana/kiwis/test_2.py as shown below because as I said above, by default, Pytest can run any folders like apples, oranges, bananas and kiwis. *My answer explains it:

此外，在默认情况下，您可以运行Apple/test_1.py、Apple/oranges/test_2.py、bananas/test_1.py和banana/kiwis/test_2.py中的所有测试，如下所示，因为正如我在上面所说的，在默认情况下，Pytest可以运行任何文件夹，如Apple、Oranges、Banana和Kiwis。*我的回答解释了这一点：

project
 |-pytest.ini
 |-apples
 |  |-__init__.py
 |  |-test_1.py # Here
 |  └-oranges
 |     |-__init__.py
 |     └-test_2.py # Here
 └-bananas
    |-__init__.py
    |-test_1.py # Here
    └-kiwis
       |-__init__.py
       └-test_2.py Here