Writing Tests with Marionette
Marionette itself is a remote driver, but we have a test runner integrated with our python marionette client that's designed with Marionette in mind. This test runner can run tests according to environment (desktop browser, Fennec on emulator, etc.). For these kinds of tests, you'll need to write Marionette Python tests.
Types of Tests Supported
The test runner supports Marionette Python tests, which are similar to Selenium tests.