zai-proxy/notes/bf-2kk.md

Task BF-2KK: Response Validation Unit Tests

Summary

All unit tests for response validation failures already exist in proxy/response_validation_test.go and pass successfully with race detector enabled.

Test Coverage Verification

1. Empty JSON Body (Non-Streaming) ✅

Test: TestResponseValidation_EmptyJSONNonStreaming

• Covers MAX_RETRIES=1, 2, and 5
• Verifies 502 Bad Gateway returned after exhausting retries
• Verifies exact upstream call count (1 + MAX_RETRIES)
• Verifies exponential backoff timing

Result: PASS (35.03s with -race)

2. Invalid JSON Body (Non-Streaming) ✅

Test: TestResponseValidation_InvalidJSONNonStreaming

• Covers malformed JSON, truncated JSON, and garbage data
• Verifies 502 Bad Gateway returned after exhausting retries
• Verifies exact upstream call count (1 + MAX_RETRIES)

Result: PASS (11.01s with -race)

3. Empty Streaming Response (Zero Bytes) ✅

Test: TestResponseValidation_EmptyStreaming

• Covers MAX_RETRIES=1, 2, and 4
• Verifies 502 Bad Gateway returned after exhausting retries
• Verifies exact upstream call count (1 + MAX_RETRIES)
• Verifies exponential backoff timing

Result: PASS (19.02s with -race)

4. Streaming Zero-Byte Detection ✅

Test: TestResponseValidation_StreamingZeroBytesPeek

• Tests zero bytes on first peek triggers retry
• Tests non-zero bytes on first peek passes through

Result: PASS (1.00s with -race)

5. Metric Assertions ✅

Tests:

• TestResponseValidation_MetricsEmptyJSON - Verifies error_type="truncated_response"
• TestResponseValidation_MetricsInvalidJSON - Verifies error_type="truncated_response"
• TestResponseValidation_MetricsEmptyStreaming - Verifies error_type="empty_streaming"

Coverage:

• zai_proxy_upstream_errors_total increments correctly
• zai_proxy_retry_attempts_total increments correctly
• Upstream call counts verified

Result: All PASS (13.02s total with -race)

6. Additional Coverage ✅

Tests:

• TestResponseValidation_ValidResponsePassesThrough - Ensures valid responses don't trigger retries
• TestResponseValidation_VariousInvalidBodies - Comprehensive invalid body test matrix

Acceptance Criteria Status

Criterion	Status	Notes
Tests in proxy/response_validation_test.go	✅	File exists with comprehensive coverage
Empty/invalid JSON (non-streaming) coverage	✅	Multiple test cases with various MAX_RETRIES
Zero-byte streaming coverage	✅	Multiple test cases with various MAX_RETRIES
Upstream call count assertions	✅	All tests verify 1 + MAX_RETRIES
Metric assertions for upstream errors	✅	Dedicated metric tests verify error_type labels
go test ./proxy/ -run TestResponseValidation -race	✅	PASS in 86.118s

Test Execution

go test ./proxy/ -run TestResponseValidation -v -race

Output: All 15 test cases PASS

Notes

The tests use the test infrastructure from bf-3zp (helpers_test.go), including:

• createTestProxyHandler() - Creates configured ProxyHandler instances
• CreateNonStreamingRequestBody() / CreateStreamingRequestBody() - Request builders
• ConfigureTestEnv() - Test environment setup
• Metric reset and verification utilities

No additional work was required - the tests were already comprehensive and passing.