unit testing - Python unittest passing arguments

Question

In Python, how would I pass an argument from the command line to a unittest function?

Here is the code so far… I know it's wrong.

class TestingClass(unittest.TestCase):

    def testEmails(self):
        assertEqual(email_from_argument, "my_email@example.com")


if __name__ == "__main__":
    unittest.main(argv=[sys.argv[1]])
    email_from_argument = sys.argv[1]

Answer 1

So the doctors here that are saying "You say that hurts? Then don't do that!" are probably right. But if you really want to, here's one way of passing arguments to a unittest test:

import sys
import unittest

class MyTest(unittest.TestCase):
    USERNAME = "jemima"
    PASSWORD = "password"

    def test_logins_or_something(self):
        print('username:', self.USERNAME)
        print('password:', self.PASSWORD)


if __name__ == "__main__":
    if len(sys.argv) > 1:
        MyTest.USERNAME = sys.argv.pop()
        MyTest.PASSWORD = sys.argv.pop()
    unittest.main()

That will let you run with:

python mytests.py myusername mypassword

You need the argv.pops, so your command line parameters don't mess with unittest's own...

The other thing you might want to look into is using environment variables:

import os
import unittest

class MyTest(unittest.TestCase):
    USERNAME = "jemima"
    PASSWORD = "password"

    def test_logins_or_something(self):
        print('username:', self.USERNAME)
        print('password:', self.PASSWORD)

if __name__ == "__main__":
    MyTest.USERNAME = os.environ.get('TEST_USERNAME', MyTest.USERNAME)
    MyTest.PASSWORD = os.environ.get('TEST_PASSWORD', MyTest.PASSWORD)
    unittest.main()

That will let you run with:

TEST_USERNAME=ausername TEST_PASSWORD=apassword python mytests.py

And it has the advantage that you're not messing with unittest's own argument parsing. The downside is it won't work quite like that on Windows...