How to run a specific test case in django-filer (or other plugins)


I’m currently struggling running a specific test or test case of django-filer add-on. (running all tests is ok)
The documentation say

# run a specific testcase in specific environment
    tox -e py27-dj18 -- test filer.tests.models.FilerApiTests.test_create_folder_structure

Sadly this does not work. Seems to be related to a previous test system.

Can you help me ? I’m working on django-filer features and need to run tests faster.