<!-- Issue title: [brief description of bug] --> Refer to [this issue](https://github.com/TEAMMATES/teammates/pull/13222#discussion_r1957340592) This issue may, however, could potentially be closed since it does not fulfill linting if a solution is made. <br> - **Environment**: <!-- The environment in which you encountered the bug, e.g. live server at `V8.0.0`, `master` branch at commit 1234567. --> master <br> **Steps to reproduce** Create a test case and pass in a `null` uuid into `getUuidFromString()` in the `Action.java` file. It should throw a `NullPointerException` <br> **Expected behaviour** Throws `InvalidHttpParameterException` <br> **Actual behaviour** Throws `NullPointerException` <br> **Additional info** <!-- You can enter any additional relevant info here. --> <!-- If you know what caused the bug and/or how to resolve the bug, you can include them in this section. --> This was just a small issue when migrating test cases. I'll handle the issue.