Module setup

Normally when you create a class in a doctest, it will have the __module__ attribute of '__builtin__'. This is sometimes not desirable. Let’s demonstrate the behavior:

>>> class Foo(object):
...    pass

>>> 'builtin' in Foo.__module__
True

By using zope.testing.module.setUp this can be controlled. Normally you set up your tests with it, but in this case we’ll just call it manually.

To call this function manually, we need to set up a fake test object. This because the setUp function expects a test with at least the globs dictionary attribute being present. Let’s make such a fake test object, using the globals of the doctest:

>>> class FakeTest(object):
...     def __init__(self):
...        self.globs = globals()

>>> test = FakeTest()

We can now call the setUp function:

>>> from zope.testing.module import setUp
>>> setUp(test)

We will now demonstrate that the __module__ argument is something else, in this case the default, __main__:

>>> class Foo(object):
...     pass
>>> Foo.__module__
'__main__'

Calling dir on the module will yield the expected attributes, including the FakeTest class we added above.

>>> import __main__
>>> attrs = dir(__main__)
>>> "FakeTest" in attrs
True

Let’s tear this down again using tearDown:

>>> from zope.testing.module import tearDown
>>> tearDown(test)

We should now be back to the original situation:

>>> class Foo(object):
...    pass
>>> 'builtin' in Foo.__module__
True

Importing

Let’s now imagine a more complicated example, were we actually want to be able to import the fake module as well:

>>> setUp(test, 'fake')
>>> a = 'Hello world'

The import should not fail:

>>> import fake
>>> fake.a
'Hello world'

Let’s tear it down again:

>>> tearDown(test)

>>> import fake
Traceback (most recent call last):
 ...
ModuleNotFoundError: No module named 'fake'

If we enter a dotted name, it will actually try to place the fake module in that dotted name:

>>> setUp(test, 'zope.testing.unlikelymodulename')
>>> a = 'Bye world'
>>> import zope.testing.unlikelymodulename
>>> zope.testing.unlikelymodulename.a
'Bye world'
>>> from zope.testing import unlikelymodulename
>>> unlikelymodulename.a
'Bye world'
>>> tearDown(test)

>>> import zope.testing.unlikelymodulename
Traceback (most recent call last):
 ...
ModuleNotFoundError: No module named 'zope.testing.unlikelymodulename'

This only works for packages that already exist:

>>> setUp(test, 'unlikelynamespacename.fake')
Traceback (most recent call last):
  ...
KeyError: 'unlikelynamespacename'

Even so, we still need to tear down:

>>> tearDown(test)
Traceback (most recent call last):
  ...
KeyError: 'unlikelynamespacename'