python – unittest无法发现/运行测试

这是我的目录树：

? tree abc_backend
abc_backend/
├── backend_main.py
├── FundDatabase.db
├── healthcheck.py
├── __init__.py
├── init.py
├── portfolio.py
├── private.py
├── __pycache__
├── questionnaire.py
├── recurring.py
├── registration.py
├── tests
│ ├── config.py
│ ├── __init__.py
│ ├── __pycache__
│ ├── test_backend.py
│ ├── test_healthcheck.py
│ └── test_private.py
├── trading.py
├── Users.db
├── VERSION
└── visualisation.py

unittest无法找到任何东西：

top ? python -m unittest abc_backend

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK

甚至不在abc_backend中：

abc_backend ? python -m unittest tests

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK

我已经验证的内容：

>我的测试方法正确命名(test_whatever)
>我的测试用例扩展了unittest.TestCase
> abc_backend和abc_backend / tests目录有一个(空)__ init__.py
>所有测试模块都是可导入的(见下文)
> unittest discover发现测试,但是相对导入存在问题(见下文)
>鼻子能够发现和运行测试,没有问题

我想了解：

>为什么我需要将发现传递给unittest以强制它发现测试？如果没有discover子命令,unittest会做什么？ (我认为unittest默认测试发现).根据documentation：

python -m unittest is the equivalent of python -m unittest discover

>一旦发现测试(通过强制发现子命令),为什么我有导入问题？

测试模块是可导入的

? python
Python 3.4.3 (default,Oct 14 2015,20:28:29) 
[GCC 4.8.4] on linux
Type "help","copyright","credits" or "license" for more information.
>>> import abc_backend.tests
>>> import abc_backend.tests.test_private
>>> import abc_backend.tests.test_healthcheck
>>> import abc_backend.tests.test_backend

unittest discover有相对进口的问题

如果我从顶部目录运行它：

top ? python -m unittest discover abc_backend
======================================================================
ERROR: tests.test_private (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/case.py",line 58,in testPartExecutor
    yield
  File "/usr/lib/python3.4/unittest/case.py",line 577,in run
    testMethod()
  File "/usr/lib/python3.4/unittest/loader.py",line 32,in testFailure
    raise exception
ImportError: Failed to import test module: tests.test_private
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/loader.py",line 312,in _find_tests
    module = self._get_module_from_name(name)
  File "/usr/lib/python3.4/unittest/loader.py",line 290,in _get_module_from_name
    __import__(name)
  File "/foo/bar/abc_backend/tests/test_private.py",line 6,in <module>
    from .. import init
ValueError: attempted relative import beyond top-level package

如果我从abc_backend中运行它：

abc_backend ? python -m unittest discover tests

======================================================================
ERROR: test_private (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/case.py",in testFailure
    raise exception
ImportError: Failed to import test module: test_private
Traceback (most recent call last):
  File "/usr/lib/python3.4/unittest/loader.py",in <module>
    from .. import init
SystemError: Parent module '' not loaded,cannot perform relative import