Writing unit tests with Python is a joy, especially with the excellent mock library.
You can tweak the language and mock almost anything to your will, making testing even the smallest of units very easy.
HOWEVER , mocking imports, when a class / module depends on imports which you might not have on your machine, such as windows modules (oei vei) when you are (and you should be) on a nix machine.
Another typical case is when you integrate a module to a big system, which imports THE ENTIRE INTERNETZ in each file.
In those cases it’s critical to be able to isolate your class / module by totally disconnecting it from those modules.
Mock to the rescue:
TLDR: you can clone
git://gist.github.com/3039780.git and play around with it…
Running nosetest now will yield the following :
To fix this, we need to mock the “the internetz” module:
The reason to put all the patches, mocks and imports in the
setUp function is that you’d probably reuse them in the same test class on other test methods.