Running a single test from unittest.TestCase via the command line

In our team, we define most test cases like this:

One "framework" class ourtcfw.py:

import unittest

class OurTcFw(unittest.TestCase):
    def setUp:
        # Something

    # Other stuff that we want to use everywhere

And a lot of test cases like testMyCase.py:

import localweather

class MyCase(OurTcFw):

    def testItIsSunny(self):
        self.assertTrue(localweather.sunny)

    def testItIsHot(self):
        self.assertTrue(localweather.temperature > 20)

if __name__ == "__main__":
    unittest.main()

When I'm writing new test code and want to run it often, and save time, I do put "__" in front of all other tests. But it's cumbersome, distracts me from the code I'm writing, and the commit noise this creates is plain annoying.

So, for example, when making changes to testItIsHot(), I want to be able to do this:

$ python testMyCase.py testItIsHot

and have unittest run only testItIsHot()

How can I achieve that?

I tried to rewrite the if __name__ == "__main__": part, but since I'm new to Python, I'm feeling lost and keep bashing into everything else than the methods.

Solution 1:

This works as you suggest - you just have to specify the class name as well:

python testMyCase.py MyCase.testItIsHot

Solution 2:

If you organize your test cases, that is, follow the same organization like the actual code and also use relative imports for modules in the same package, you can also use the following command format:

python -m unittest mypkg.tests.test_module.TestClass.test_method

# In your case, this would be:
python -m unittest testMyCase.MyCase.testItIsHot

Python 3 documentation for this: Command-Line Interface

Solution 3:

It can work well as you guess

python testMyCase.py MyCase.testItIsHot

And there is another way to just test testItIsHot:

    suite = unittest.TestSuite()
    suite.addTest(MyCase("testItIsHot"))
    runner = unittest.TextTestRunner()
    runner.run(suite)

Solution 4:

If you check out the help of the unittest module it tells you about several combinations that allow you to run test case classes from a module and test methods from a test case class.

python3 -m unittest -h

[...]

Examples:
  python3 -m unittest test_module               - run tests from test_module
  python3 -m unittest module.TestClass          - run tests from module.TestClass
  python3 -m unittest module.Class.test_method  - run specified test method
```lang-none

It does not require you to define a `unittest.main()` as the default behaviour of your module.