If you append a `[]` to the end of this command it will allow `tox` to optionally accept command line arguments for `nosetests`.  

```
[testenv]
commands = python setup.py nosetests []
```
This will allow others to run specific tests or enable some other `nose` features.

For example, in order to verbosely run the `test_aweber_api` test across all of the supported Tox environments.:

`env/bin/tox --  -v -x test/test_aweber_api.py`