test: add unit tests for response-cache headers

[shauryavardhan1307]

Summary

The file src/lib/response-cache.ts currently has no
test coverage. A previous issue was closed without a PR
and the test file test/response-cache.test.ts does
not exist.

Changes Needed

• Create test/response-cache.test.ts with Vitest tests
• Test all functions in src/lib/response-cache.ts
• Cover edge cases and error handling

Impact

• Improves test coverage for response cache utilities
• Prevents regressions in cache header functionality
• Consistent test coverage across the codebase

I'd like to work on this if approved!
GSSoC '26 contributor.

[ThePriyanuj]

Hi @Priyanshu-byte-coder,

I would love to take on this assignment to build out the complete unit testing suite for the response cache header utilities! I have my local development workspace configured and am ready to implement deep, robust coverage using Vitest.

🧪 My Planned Testing Blueprint (test/response-cache.test.ts):

1. Cache-Control Directive Assertions:

   • I will verify that the utility functions generate exact, correctly formatted HTTP Cache-Control string directives (e.g., parsing variations of public, max-age, s-maxage, and stale-while-revalidate).
   • Write test vectors to ensure conditional parameters (like custom CDN cache-tags or revalidation triggers) inject seamlessly into header objects.

2. Mock Response Ingestion:

   • Build out mock Node.js/Next.js response stubs to verify that the target utilities safely execute .setHeader() or update headers maps, asserting that pre-existing headers are not destructively overwritten unless explicitly intended.

3. Boundary & Edge-Case Resilience:

   • Malformed/Negative TTL Bounds: Test how the utilities respond to unexpected inputs like zero, negative numbers, or invalid strings for cache durations. I will assert that they gracefully fallback to safe default headers (no-store, max-age=0) to protect the runtime.
   • Headers Isolation: Ensure that dynamic headers (like Vary or custom telemetry tags) mutate in complete isolation without leaking cache instructions across concurrent mock response streams.

I can spin this up immediately and deliver a clean, modular, and fully documented test file that brings up the repository's test coverage metrics. Please assign this issue to me!

[srinidhi-2006-bit]

/assign

[aarushlohit]

/take /claim

[aarushlohit]

/assign

[Bhavy12-cell]

Hi @Priyanshu-byte-coder
Please assign me this issue.

[github-actions]

Assigned to @Bhavy12-cell! You have 7 days to open a PR. No PR after 7 days = auto-unassigned so others can pick it up. Good luck!

[github-actions]

Hey @Bhavy12-cell — this issue was assigned 7 days ago with no PR opened. Unassigning so others can pick it up.

Still working on it? Drop a comment and request re-assignment.