Today I have begun learning and writing unit tests for some updates I have made to existing python functions. The idea of the unit test is to make sure the updated python modules/functions/classes all produce the same results as before the update. The update is simply swapping existing module usages with new module usages. I am using python’s default unittest module and for now, I am doing test case. Per the definition on python.org, test case is defined as
A test case is the smallest unit of testing. It checks for a specific response to a particular set of inputs. unittest provides a base class, TestCase, which may be used to create new test cases.
Using the basic example on python.org
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import unittest
class TestStringMethods(unittest.TestCase):
That will create an class inheriting the unittest’s TestCase object.
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import unittest
class TestStringMethods(unittest.TestCase):
def test_upper(self):
self.assertEqual('foo'.upper(), 'FOO')
if __name__ == '__main__':
unittest.main()
This now adds a function called test_upper that will test whether foo.upper() equals to FOO. That is what assertEqual() does. There are other assert tests such as assertFalse(), assertTrue()… etc as well. It also appears that the test unit functions must start with the name test or it will not work. One thing I have also noticed from running a test like that is that it seems that it will call a form of exit() after completing the test. There is also another way to call the TestStringMethods without using
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if __name__ == '__main__':
unittest.main()
Per the website, we can replace the last two lines with these instead
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suite = unittest.TestLoader().loadTestsFromTestCase(TestStringMethods)
unittest.TextTestRunner(verbosity=2).run(suite)
Perhaps this method won’t exit out the script editor when finished. That remains to be seen when I test this out further in the near future. Either way, very cool discovery today with unit testing!