Improve test coverage for history endpoints and database behavior

[jyotish6699]

Summary

The history module currently has coverage for core CRUD operations, but several validation boundaries and database behaviors are not covered by automated tests.

Missing Coverage Areas

• Maximum code length validation (max_length=50000)
• Pagination limit boundary validation
• Search limit boundary validation
• Code preview truncation behavior
• SHA256 code hash generation
• Repeated deletion of the same history entry

Proposed Improvements

Add tests to verify:

1. Oversized code submissions are rejected.
2. Invalid pagination limits return validation errors.
3. Invalid search limits return validation errors.
4. Stored code previews are truncated correctly.
5. Generated code hashes match SHA256 output.
6. Deleting the same history entry twice returns a 404 response.

Benefits

• Improves confidence in validation behavior.
• Covers important database-specific logic.
• Helps prevent regressions in history-related functionality.
• Strengthens automated test coverage for edge cases.

Verification

All added tests pass locally:

• History test suite: 15/15 passing
• Full project test suite: 423/423 passing

[jyotish6699]

Hi @maintainers,

I would like to work on this issue under GSSoC 2026.

I have already analyzed the history module and prepared tests covering validation boundaries and database edge cases. All added tests pass locally, and the full test suite is passing as well.

Could you please assign this issue to me?

Thank you!

[Aryanbansal-05]

Hi @komalharshita!
This was a challenging issue to work through but really enjoyed solving it! Submitted PR #834, all 72 tests passing. Would love your review!