Setup does not run any tests

Looks like setuptools does not run any tests; is something messed up with the config?

```sh
sascha@jessie:~/src/fontmake$ python setup.py test
running test
running egg_info
writing requirements to Lib/fontmake.egg-info/requires.txt
writing Lib/fontmake.egg-info/PKG-INFO
writing top-level names to Lib/fontmake.egg-info/top_level.txt
writing dependency_links to Lib/fontmake.egg-info/dependency_links.txt
writing entry points to Lib/fontmake.egg-info/entry_points.txt
reading manifest file 'Lib/fontmake.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
warning: no files found matching '*.glyphs' under directory 'tests'
warning: no files found matching '*.designspace' under directory 'tests'
warning: no files found matching '*.plist' under directory 'tests'
writing manifest file 'Lib/fontmake.egg-info/SOURCES.txt'
running build_ext

----------------------------------------------------------------------
Ran 0 tests in 0.000s

OK
```

Start with setup.py and the tests directory, then reproduce the issue with `python setup.py test`. Trace why the test command discovers zero tests and adjust the configuration so the existing suite is collected; done means the command runs the tests rather than reporting `Ran 0 tests`.

Written by the indexing model from the issue text.