Mismatch in coverage percentage - GoLang Native fuzzing (Envoy/Gateway)

[sudiptob2]

Although #13333 fixes the broken coverage reporting in OSS-Fuzz, we noticed that the coverage percentage still differs when compared to running coverage locally using Go’s testing tools.

The following commands are used to collect local coverage in envoy/gateway

# Build the fuzz test binary with coverage support
go test -c \
  -coverpkg=../../../gateway/... \
  -covermode=atomic \
  -o /path/to/fuzz_test_binary \
  github.com/envoyproxy/gateway/test/fuzz

# Run the fuzz test and generate coverage data
go tool test2json -t /path/to/fuzz_test_binary \
  -test.v \
  -test.paniconexit0 \
  -test.run ^FuzzGatewayAPIToXDS$ \
  -test.coverprofile /path/to/output/coverage.out

After that we generated coverage using oss-fuzz infra following the instructions given in this docs. and using the branch in #13333

Attachments

1. Coverage generated using OSS-Fuzz infra (Google Drive)
2. Coverage generated locally (Google Drive Link)