How to run unittest discover from "python setup.py test"?

I'm trying to figure out how to get python setup.py test to run the equivalent of python -m unittest discover. I don't want to use a run_tests.py script and I don't want to use any external test tools (like nose or py.test). It's OK if the solution only works on python 2.7.

In setup.py, I think I need to add something to the test_suite and/or test_loader fields in config, but I can't seem to find a combination that works correctly:

config = {
    'name': name,
    'version': version,
    'url': url,
    'test_suite': '???',
    'test_loader': '???',
}

Is this possible using only unittest built into python 2.7?

FYI, my project structure looks like this:

project/
  package/
    __init__.py
    module.py
  tests/
    __init__.py
    test_module.py
  run_tests.py <- I want to delete this
  setup.py

Update: This is possible with unittest2 but I want find something equivalent using only unittest

From https://pypi.python.org/pypi/unittest2

unittest2 includes a very basic setuptools compatible test collector. Specify test_suite = 'unittest2.collector' in your setup.py. This starts test discovery with the default parameters from the directory containing setup.py, so it is perhaps most useful as an example (see unittest2/collector.py).

For now, I'm just using a script called run_tests.py, but I'm hoping I can get rid of this by moving to a solution that only uses python setup.py test.

Here's the run_tests.py I'm hoping to remove:

import unittest

if __name__ == '__main__':

    # use the default shared TestLoader instance
    test_loader = unittest.defaultTestLoader

    # use the basic test runner that outputs to sys.stderr
    test_runner = unittest.TextTestRunner()

    # automatically discover all tests in the current dir of the form test*.py
    # NOTE: only works for python 2.7 and later
    test_suite = test_loader.discover('.')

    # run the test suite
    test_runner.run(test_suite)

If you use py27+ or py32+, the solution is pretty simple:

test_suite="tests",