Add unit tests for the http-handlers

[awhvish]

Implement these commands specifically:
go test ./cmd/server/ -v

Run with coverage
go test ./cmd/server/ -cover

• ensure consistent status codes across all endpoints
• how the server handles special characters in key/value
• all possible edges cases of non-existent keys, empty inputs and different handler's response

Refer to Go testing package to learn to write unit tests.

[Omkarop0808]

I would like to work on this issue , please assign it to me.

[awhvish]

alright

[Omkarop0808]

Hi @awhvish,
Completed #8! Quick question: would it make sense to relabel this from "easy" to "medium"?
The implementation required:

• 443 lines of test code (9 functions, 29 sub-tests)
• Mock store creation without Raft
• Complex edge case handling (unicode, special chars, concurrency)
• URL encoding and file cleanup logic
  Just thinking it might help set expectations for future contributors. Either way, happy to have contributed!,happy to make any adjustment if required.