Add tests for Eliminates duplicate Canvas API calls

Overview: This moves the appropriate controller methods tests from test_controller.py to test_canvas.py. 

Some are updated as appropriate, but the tests are by and large the same.

Lines 12-15 are new. It accommodates  the new CanvasModules class that allows us to get rid of patching for the controller methods tests.

Are all of these imports still being used given the moving around of tests?