move test to tests

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
append .tox to avoid going in there

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>
make sure we don't hard code the path for py.test

Signed-off-by: Alfredo Deza <alfredo.deza@inktank.com>