Subscription Manager

John Doe has left the project, and he didn't finish his work.

You will take on his work!

For some legal reason, you may use Google Search to do the work but not any LLM AI based tool.

Your first task

Create a new Git branch named FixTest
Understand the code with the help of your colleagues
Make the test passing
Commit the changes with the comment "tests fixed"

Your second task

The product owner has a new requirement: A customer can not subscribe twice to the same subscription.

Explain how you will proceed to your colleague
Add the test and code to implement and verify this requirement
Commit the changes with the comment "subscribe once"

Your third task

The product owner has a new requirement: A customer should be able to unsubscribe from a subscription.

Explain how you will proceed to your colleague
Add the test and code to implement and verify this requirement
Commit the changes with the comment "subscribe once"