python-3.x - python nose --with-doctest 添加额外的测试
问题描述
我需要推迟一些库的导入,除非需要它们,所以我创建了一个对象来推迟导入。
class Importer(object):
def __init__(self, name):
self.name = name
def __bool__(self):
try:
mod = importlib.import_module(self.name)
return True
except ImportError:
return False
def __getattr__(self, name):
try:
mod = importlib.import_module(self.name)
attr = getattr(mod, name)
setattr(self, name, attr)
return attr
except ImportError as e:
msg = self.name + " must be installed"
raise ImportError(msg)
我已经完成nose
了我的测试,一切都通过了。但是,当我运行--with-doctest
它时,它会运行一个额外的测试(我尚未定义),该测试会在未安装给定库的任何环境中生成错误。
测试下面的代码会重现我遇到的问题。在没有 , 的环境中numpy
,nosetests --with-doctest
正在运行我尚未定义的第二个测试。
numpy = Importer('numpy')
def mean(array):
"""
Mean of an array.
Examples
--------
>>> mean([1, 2, 3])
2.0
>>> mean([1, -1])
0.0
"""
if numpy:
return numpy.mean(array)
return float(sum(array) / len(array))
显然,只有一个 doctest 可供测试。此外,如果numpy
已安装,则仅运行 1 个测试。那么,为什么numpy
没有安装我要进行第二次测试呢?这是输出。
.E
======================================================================
ERROR: Failure: ImportError (numpy must be installed)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/devin/Dropbox/Devin_S_+_Spark_Wave/nimble/zissue/issue.py", line 16, in __getattr__
mod = importlib.import_module(self.name)
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/importlib/__init__.py", line 126, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'numpy'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/site-packages/nose/failure.py", line 39, in runTest
raise self.exc_val.with_traceback(self.tb)
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/site-packages/nose/plugins/manager.py", line 154, in generate
for r in result:
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/site-packages/nose/plugins/doctests.py", line 228, in loadTestsFromModule
tests = self.finder.find(module)
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/doctest.py", line 933, in find
self._find(tests, obj, name, module, source_lines, globs, {})
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/doctest.py", line 992, in _find
if ((inspect.isroutine(inspect.unwrap(val))
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/inspect.py", line 512, in unwrap
while _is_wrapper(func):
File "/Users/devin/anaconda3/envs/issueEnv/lib/python3.6/inspect.py", line 503, in _is_wrapper
return hasattr(f, '__wrapped__')
File "/Users/devin/Dropbox/testing/issue/issue.py", line 22, in __getattr__
raise ImportError(msg)
ImportError: numpy must be installed
----------------------------------------------------------------------
Ran 2 tests in 0.003s
解决方案
嗯,这很有趣!
核心困难在于doctest
模块“欺骗”了您尝试 numpy 导入。也就是说,它探测了numpy.__wrapped__
,而你上钩了。您需要区分可以返回虚拟值的探测调用和必须导入或引发的真实调用。
也许启发式的测试__wrapped__
就足够了。但是您可能会发现有必要检查调用堆栈以找到调用者,注意它是例如 autodoc,并基于此更改行为。