用Python模拟恐怖
我已经试了差不多两个小时了，运气不好 我有一个模块，如下所示：用Python模拟恐怖,python,unit-testing,mocking,doctest,zope.component,Python,Unit Testing,Mocking,Doctest,Zope.component,我已经试了差不多两个小时了，运气不好 我有一个模块，如下所示： try: from zope.component import queryUtility # and things like this except ImportError: # do some fallback operations <-- how to test this? 运行测试时： aatiis@aiur ~/work/ao.shorturl $ ./bin/test --coverage . R
try:
from zope.component import queryUtility # and things like this
except ImportError:
# do some fallback operations <-- how to test this?
aatiis@aiur ~/work/ao.shorturl $ ./bin/test --coverage .
Running zope.testing.testrunner.layer.UnitTests tests:
Set up zope.testing.testrunner.layer.UnitTests in 0.000 seconds.
Error in test /home/aatiis/work/ao.shorturl/src/ao/shorturl/shorturl.txt
Traceback (most recent call last):
File "/usr/lib64/python2.5/unittest.py", line 260, in run
testMethod()
File "/usr/lib64/python2.5/doctest.py", line 2123, in runTest
test, out=new.write, clear_globs=False)
File "/usr/lib64/python2.5/doctest.py", line 1361, in run
return self.__run(test, compileflags, out)
File "/usr/lib64/python2.5/doctest.py", line 1282, in __run
exc_info)
File "/usr/lib64/python2.5/doctest.py", line 1148, in report_unexpected_exception
'Exception raised:\n' + _indent(_exception_traceback(exc_info)))
File "/usr/lib64/python2.5/doctest.py", line 1163, in _failure_header
out.append(_indent(source))
File "/usr/lib64/python2.5/doctest.py", line 224, in _indent
return re.sub('(?m)^(?!$)', indent*' ', s)
File "/usr/lib64/python2.5/re.py", line 150, in sub
return _compile(pattern, 0).sub(repl, string, count)
File "/usr/lib64/python2.5/re.py", line 239, in _compile
p = sre_compile.compile(pattern, flags)
File "/usr/lib64/python2.5/sre_compile.py", line 507, in compile
p = sre_parse.parse(p, flags)
AttributeError: 'NoneType' object has no attribute 'parse'
Error in test BaseShortUrlHandler (ao.shorturl)
Traceback (most recent call last):
File "/usr/lib64/python2.5/unittest.py", line 260, in run
testMethod()
File "/usr/lib64/python2.5/doctest.py", line 2123, in runTest
test, out=new.write, clear_globs=False)
File "/usr/lib64/python2.5/doctest.py", line 1351, in run
self.debugger = _OutputRedirectingPdb(save_stdout)
File "/usr/lib64/python2.5/doctest.py", line 324, in __init__
pdb.Pdb.__init__(self, stdout=out)
File "/usr/lib64/python2.5/pdb.py", line 57, in __init__
cmd.Cmd.__init__(self, completekey, stdin, stdout)
File "/usr/lib64/python2.5/cmd.py", line 90, in __init__
import sys
File "<doctest shorturl.txt[10]>", line 4, in fakeimport
NameError: global name 'realimport' is not defined
shorturl.txtao.shorturl>>> import zope # ok, this raises an ImportError
>>> reload(ao.shorturl) <module ...>
只需将monkeypatch插入
内置程序\uuuuu import\uuuuuutry:
import builtins
except ImportError:
import __builtin__ as builtins
realimport = builtins.__import__
def myimport(name, globals, locals, fromlist, level):
if ...:
raise ImportError
return realimport(name, globals, locals, fromlist, level)
builtins.__import__ = myimport
…名称=='zope.component'\uuuuuuuu导入\uuuuuuuu或从zope.component导入的，而是从zope导入的，那么名称将是'zope'
，并且'component'
将是from列表中的唯一项
编辑：用于\uuuu导入
函数的文档说要导入的名称是内置的
（如Python 3），但事实上您需要\uu内置的
——我已经编辑了上面的代码，以便它可以以任何方式工作。这就是我在单元测试中调整的
它使用。（警告：我链接的PEP-302文档和更简洁的发行说明并不准确。）
我使用meta_路径
，因为它在导入序列中尽可能早
如果模块已经被导入（就像我的情况一样，因为早期的unittests针对它进行模拟），那么在对依赖模块执行重新加载之前，有必要将其从sys.modules中删除
Ensure we fallback to using ~/.pif if XDG doesn't exist.
>>> import sys
>>> class _():
... def __init__(self, modules):
... self.modules = modules
...
... def find_module(self, fullname, path=None):
... if fullname in self.modules:
... raise ImportError('Debug import failure for %s' % fullname)
>>> fail_loader = _(['xdg.BaseDirectory'])
>>> sys.meta_path.append(fail_loader)
>>> del sys.modules['xdg.BaseDirectory']
>>> reload(pif.index) #doctest: +ELLIPSIS
<module 'pif.index' from '...'>
>>> pif.index.CONFIG_DIR == os.path.expanduser('~/.pif')
True
>>> sys.meta_path.remove(fail_loader)
要回答为什么新重新加载的模块具有旧加载和新加载的属性的问题，这里有两个示例文件
第一个是模块y
，带有导入失败案例
# y.py
try:
import sys
_loaded_with = 'sys'
except ImportError:
import os
_loaded_with = 'os'
第二个是x
，它演示了在重新加载时为模块保留句柄如何影响其属性
# x.py
import sys
import y
assert y._loaded_with == 'sys'
assert y.sys
class _():
def __init__(self, modules):
self.modules = modules
def find_module(self, fullname, path=None):
if fullname in self.modules:
raise ImportError('Debug import failure for %s' % fullname)
# Importing sys will not raise an ImportError.
fail_loader = _(['sys'])
sys.meta_path.append(fail_loader)
# Demonstrate that reloading doesn't work if the module is already in the
# cache.
reload(y)
assert y._loaded_with == 'sys'
assert y.sys
# Now we remove sys from the modules cache, and try again.
del sys.modules['sys']
reload(y)
assert y._loaded_with == 'os'
assert y.sys
assert y.os
# Now we remove the handles to the old y so it can get garbage-collected.
del sys.modules['y']
del y
import y
assert y._loaded_with == 'os'
try:
assert y.sys
except AttributeError:
pass
assert y.os
如果您不介意更改程序本身，也可以将导入调用放入函数中，并在测试中对其进行修补。啊，谢谢！出于某种原因，我尝试执行def\uu import\uu（）
，但没有将其分配给内置；我真傻。有趣的是，我正在这里读你的答案：-你认为如果我不将queryUtility导入到我的模块的作用域中，情况会变得更容易吗？@Attila，如果你从zope import component
导入，然后使用component.queryUtility
，它会让你更容易，例如，在某些时候使用真实的东西，还有其他时候的仿制品。正如我在回答中所写的那样，我确实建议将其作为一个一般性的东西，这是我们在Google编写Python代码的方式的一部分（当然，有时可以使用As
子句来缩短导入的名称，但这不会改变语义），您的\uuuu import\uuuu
-like函数将'zope'
视为name
参数，将'component'
视为fromlist
参数中的一项（唯一一个，除非您从zope导入this、that、component
等；-）；因此，请确保相应地触发。感谢您的建议，我将采用这种编码方式，因为它似乎在这种情况下很有帮助。然而，我刚刚意识到你的答案对我不起作用（如果我用\uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuiuuuuuuuuuuuuuuuuuiuuuuuuuuuuuuuuuuuuuuuiuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu2.5替换的话，它在交互式控制台上确实起作用，不<。再次编辑以修复。太好了，现在我设法提出了一个ImportError
，这就是我所需要的。有趣的是：如果我重新加载ao.shorturl
，并且在其中我有try:import zope.component，zope.interface；除了ImportError:fallback（）
，我得到了zope.component
的第一个ImportError
，zope.interface仍将在ao.shorturl（ao.shorturl.zope.interface）中可用。为什么会这样？我刚刚又增加了一节来描述为什么会这样。tl；dr，您需要在重新加载之前删除ao.shorturl
。
try:
import builtins
except ImportError:
import __builtin__ as builtins
realimport = builtins.__import__
def myimport(name, globals, locals, fromlist, level):
if ...:
raise ImportError
return realimport(name, globals, locals, fromlist, level)
builtins.__import__ = myimport
Ensure we fallback to using ~/.pif if XDG doesn't exist.
>>> import sys
>>> class _():
... def __init__(self, modules):
... self.modules = modules
...
... def find_module(self, fullname, path=None):
... if fullname in self.modules:
... raise ImportError('Debug import failure for %s' % fullname)
>>> fail_loader = _(['xdg.BaseDirectory'])
>>> sys.meta_path.append(fail_loader)
>>> del sys.modules['xdg.BaseDirectory']
>>> reload(pif.index) #doctest: +ELLIPSIS
<module 'pif.index' from '...'>
>>> pif.index.CONFIG_DIR == os.path.expanduser('~/.pif')
True
>>> sys.meta_path.remove(fail_loader)
try:
import xdg.BaseDirectory
CONFIG_DIR = os.path.join(xdg.BaseDirectory.xdg_data_home, 'pif')
except ImportError:
CONFIG_DIR = os.path.expanduser('~/.pif')
# y.py
try:
import sys
_loaded_with = 'sys'
except ImportError:
import os
_loaded_with = 'os'
# x.py
import sys
import y
assert y._loaded_with == 'sys'
assert y.sys
class _():
def __init__(self, modules):
self.modules = modules
def find_module(self, fullname, path=None):
if fullname in self.modules:
raise ImportError('Debug import failure for %s' % fullname)
# Importing sys will not raise an ImportError.
fail_loader = _(['sys'])
sys.meta_path.append(fail_loader)
# Demonstrate that reloading doesn't work if the module is already in the
# cache.
reload(y)
assert y._loaded_with == 'sys'
assert y.sys
# Now we remove sys from the modules cache, and try again.
del sys.modules['sys']
reload(y)
assert y._loaded_with == 'os'
assert y.sys
assert y.os
# Now we remove the handles to the old y so it can get garbage-collected.
del sys.modules['y']
del y
import y
assert y._loaded_with == 'os'
try:
assert y.sys
except AttributeError:
pass
assert y.os