Test function regularisation

[teddychao]

Feature Description

Test functions need to generate test datafiles before the specific test starts and delete test datafiles when that test is finished. This is because we are going to move PsPM testing environment from Jenkins to GitHub Action, while the latter has a maximum storage limitation. However, currently the data generation and deletion is not in time, thus there is often some test data remaining there when the testing procedure has been completed. It may need regularisation for better handling of these files.