I was going to try to do a pure unit test, but I see this caveat in the existing unit test code in xmodule/tests/test_export.py:

        for location in initial_import.modules[course_id].keys():
            print("Checking", location)
            if location.category == 'html':
                print(
                    "Skipping html modules--they can't import in"
                    " final form without writing files..."
                )
                continue
            self.assertEquals(initial_import.modules[course_id][location],
                              second_import.modules[course_id][location])

Do you have any insight into this?