It is generally a good idea to write “unit tests” as you develop code, tests that check one small unit of the code to insure that it gives the expected output for some set of inputs.
If you are developing a Python module containing some functions, then each function might have one or more tests to go with it. Often these are designed so that running the test produces no output if the test passes, but raises some exception if it fails.
If the test functions all have the string “test” somewhere in their title, then nose can be used to easily sniff out these tests and run them all (or some subset with appropriate arguments).
To install nose on the class VM:
$ sudo apt-get install python-setuptools
$ sudo easy_install nose
You first have to install setuptools so that easy_install is available, which is often used for Python packages.
To read more about nose and see some examples: