Improve test coverage for util package (0 tests, 451 LOC)

[BrewingCoder]

Area

Backend — API / GraphQL

Category

Test coverage

Description

The util package is imported by 45 files and provides critical infrastructure (runtime modes, tracing, panic recovery, test DB setup) but has zero tests for its own code.

The irony: it provides RunTestWithDBWipe() and CreateAndMigrateTestDB() used by 12+ test files, but none of its own functions are tested.

Priority test targets:

1. GetRuntime() — valid/invalid CLI flag combinations
2. Runtime/Handler validation — IsValid(), IsPublicGraph(), IsWorker(), etc.
3. GenerateRandomString() — length, character set
4. JsonStringToStringArray() — valid JSON, invalid JSON, empty
5. RestRequest() — success, HTTP errors, JSON decode errors
6. MultiSpan tracing — Finish with/without error, SetAttribute, disabled context

See src/backend/util/MODULE.md for full analysis.

Affected Files / Packages

src/backend/util/runtime.go (84 lines — runtime mode system, no tests)
src/backend/util/tracer.go (119 lines — OTel span abstraction, no tests)
src/backend/util/tests.go (75 lines — test infra, no tests for itself)
src/backend/util/tracer-graphql.go (63 lines — GraphQL middleware, no tests)
src/backend/util/request.go (45 lines — HTTP client, no tests)
src/backend/util/recovery.go (27 lines — panic handlers, no tests)
src/backend/util/strings.go (23 lines — helpers, no tests)
src/backend/util/random.go (15 lines — random string, no tests)

[github-actions]

AI Triage: The util package with 451 LOC and 45 dependent files has zero test coverage and needs comprehensive tests for critical infrastructure functions like runtime validation, tracing, and test helpers.

Labels applied: area:backend, tech-debt, priority:medium, component:graphql