fooling imported script so it can import module which does not exist

Question

I'm writing foobaz python app which uses plugins (in rules/plugins/ directory) and tests to these plugins (in rules/tests/ ) from project foobar . I do not control these (both plugins and their tests).

Because of import statements in the tests, I can not figure out how to run these. Test looks like this:

$ cat rules/tests/test_something.py
import unittest

from foobar.rules.plugins import something

class TestSomething(unittest.TestCase):
    def test_something_equals(self):
        self.assertEqual(1, something.equals(1))

Plugin itself can look like this:

$ cat rules/plugins/something.py
def equals(i):
  return i

And script I'm using to run all the tests look like this:

$ cat tests.py 
#!/usr/bin/env python

import sys
import unittest

sys.path.append('rules/tests/')
from test_something import TestSomething

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

When I want to execute the tests, I (no surprise) get:

$ ./tests.py 
Traceback (most recent call last):
  File "./tests.py", line 8, in <module>
    from test_something import TestSomething
  File "rules/tests/test_something.py", line 6, in <module>
    from foobar.rules.plugins import something
ImportError: No module named foobar.rules.plugins

Is there some way I can get this running given I can not edit plugin or test?

If I could edit test, I would do:

- from foobar.rules.plugins import something
+ import sys
+ sys.path.append('rules/plugins/')
+ import something

and it would work (tested).

Answer 1

OK, after a discussion with a colleagues, there is a really simple way how to resolve this:

$ mkdir foobar
$ mv rules/ foobar/
$ touch foobar/__init__.py
$ touch foobar/rules/__init__.py
$ touch foobar/rules/plugins/__init__.py

This way test will be able to find what it needs. I did not realized this obvious thing before.