Question

I have a bunch of modules and for each module I have a unittest based test. I want to define the main in each module to run its tests, but I get import errors because of import loops (specifically when I use from mymodule import myclass in the test.
I suspect this is a solved problem, so – what should I put in my module’s main to run its corresponding test?

Answer 1

If I understand you correctly, you’ve got a file (lets call it mymodule.py) that looks like this:

import unittest
from mymoduletests import MyModuleTests

class myclass(object):
    def somefunction(self, x):
        return x*x

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

and a separate file (lets call it mymoduletests.py) that looks something like this:

import unittest
from mymodule import myclass

class MyModuleTests(unittest.TestCase):
    def test_somefunction(self):
        m = myclass()
        self.assertEqual(4, m.somefunction(2))

If you run mymodule.py you get the following result:

Traceback (most recent call last):
  File "mymodule.py", line 2, in <module>
    from mymoduletests import MyModuleTests
  File "/Users/srgerg/Desktop/p/mymoduletests.py", line 2, in <module>
    from mymodule import myclass
  File "/Users/srgerg/Desktop/p/mymodule.py", line 2, in <module>
    from mymoduletests import MyModuleTests
ImportError: cannot import name MyModuleTests

However, if you change mymodule.py to this:

class myclass(object):
    def somefunction(self, x):
        return x*x

if __name__ == '__main__':
    import unittest
    from mymoduletests import MyModuleTests
    unittest.main()

and then run it, you get:

.
----------------------------------------------------------------------
Ran 1 test in 0.000s

OK

Have I understood you correctly?