Task 3.4: Fix compression.test.ts

[kluth]

Phase: 3 - Fix Existing Failing Tests (High Priority)

Tags: bug-fix, performance

Description:
Analyze and fix the failure in tests/performance/compression.test.ts (uncaught exception, likely related to streaming).

Acceptance Criteria:

• Analyze the failure in tests/performance/compression.test.ts
• Fix uncaught exception issues (likely streaming-related)
• Ensure test passes
• Verify no regressions in other tests

[kluth]

Phase 3 Progress: Task 3.4 FIXED ✅

Compression Tests Fixed

All 4 failing compression middleware tests have been FIXED and committed.

Tests Fixed:

1. ✅ compression middleware should compress large responses
2. ✅ brotliCompression should prefer brotli when available
3. ✅ gzipCompression should use gzip encoding
4. ✅ compression middleware should handle writeHead override

Root Cause & Fix:

Bug 1: Invalid contentTypes in convenience wrappers (src/performance/compression.ts:238, 245)

• brotliCompression() was passing contentTypes: ['br'] (invalid - 'br' is encoding, not content type)
• gzipCompression() was passing contentTypes: ['gzip'] (invalid - 'gzip' is encoding, not content type)
• These prevented any content from being compressed
• Fix: Removed invalid contentTypes overrides

Bug 2: Test timing issue (tests/performance/compression.test.ts)

• Tests checked Content-Encoding header before writeHead() call
• Middleware only sets Content-Encoding inside writeHead override
• Fix: Added res.writeHead(200) calls before assertions

Bug 3: Mock writeHead signature handling (tests/performance/compression.test.ts:27-41)

• Mock didn't handle both writeHead(code, headers) and writeHead(code, message, headers) signatures
• Fix: Updated mock to correctly detect and merge headers

Commits:

• fe88669: fix: Fix compression middleware tests and contentTypes configuration

Verification:

• Standalone debug script confirms middleware correctly sets Content-Encoding
• All 4 tests now pass
• Full test suite compiling and running (106/110 total tests passing - 96.4%)

Next: Continue with remaining Phase 3 tests or proceed to Phase 4 Risk Mitigation