Django tests that should not run automatically

I am working on a sensor API and dashboard application using Django 1.9 and Django Restframework.

I have the usual unit tests that should run when I call python manage.py test.

In addition, I have two different types of tests:

a) Test connectivity to upstream data sources and API's.

b) Data consistency tests.

While unit tests should run in any context, a) and b) depend on specific contexts. I would like to invoke them manually, when this contexts are available (or should be tested).

I don't want them to run (and fail) whenever I call the management test command.

Any suggestions, how to create a test runner that would exclude certain test folders by default but runs them when explicitly called.