Python unittest and discovery

I ran into the same issue when running python -m unittest discover. Here is a good checklist to verify your setup. Nose is more flexible with the allowed configurations, but not necessarily better.

1. Make sure all files/directories start with test. Do not use test-something.py, since that is not a valid Python module name. Use test_something.py.

2. If you are putting your tests in a sub-directory (e.g. test/), make sure you create a test/__init__.py file so python will treat the directory as a package.

3. All class test cases definitions must be extend unittest.TestCase. For example,

   class DataFormatTests(unittest.TestCase)
   

4. All test cases methods definitions must start with test_

    def test_data_format(self):