The code changes involved updating the system to manage websockets from the server side, which removed the necessity to hardcode the websocket URL. Furthermore, an implementation to configure host and port of the game server was added. This included setup functions and their usage in chat and data exchange servers. Tests were updated to reflect these changes as well.

Expanded the tests in the 'test_study_server.py' file to include testing for tutorial connectivity. Added tests in 'test_start.py' to test the functionality of PlateDispenser and Sink game items. This included tests to validate the handling of dirty and clean plates and testing item drops and pick-ups. Various adjustments were made to players' positions to accommodate the tests.

The refactoring involved creating a new function to handle game server requests for cleaner and more concise code. Changes were also made to the formatting of commit messages for better readability. Invalid game environment configurations are now dealt with accordingly to prevent game errors. Several updates were made to the tests to ensure they accurately measure the performance and functionality of the game.