tracingtest

Overview ¶

Package tracingtest provides an in-process, stdlib-only Tracer fixture for tests. It is intentionally test-only: production code wires the OTel adapter (adapters/otel) via bootstrap.WithTracer, falling back to kernel/wrapper.NoopTracer{} when no tracer is configured.

Deliberate propagation asymmetry (B2-A-20) ¶

simpleTracer is in-process-only by design:

• INBOUND (trace-ID reuse only, NOT parent-span linking): Start reuses an upstream trace ID that runtime/http/middleware.trace_propagation already extracted from W3C/B3 headers into kernel/pkg/ctxkeys. simpleSpan has no parentSpanID field — full parent-child span hierarchy requires the OTel adapter (adapters/otel). The OTel adapter honors inbound context the same way for the trace-ID dimension, but additionally links spans in a proper parent-child hierarchy that simpleTracer cannot express.
• OUTBOUND (asymmetric, intentional): simpleTracer NEVER injects a W3C `traceparent` header onto outbound calls. Cross-process trace propagation is exclusively the responsibility of the OTel adapter (adapters/otel, OpenTelemetry SDK + propagation.TraceContext).

This asymmetry is the reason the fixture must never reach production: a service wired with simpleTracer would silently drop cross-process trace links. The boundary is enforced by archtest TRACING-SIMPLETRACER-TEST-ONLY-01 (R-B bans non-_test.go imports of this package; R-A seals the deleted runtime/observability/tracing.NewTracer).

ref: go.opentelemetry.io/otel — Tracer/Span API, W3C TraceContext propagation (outbound injection lives in adapters/otel).

INVARIANT: TRACING-SIMPLETRACER-TEST-ONLY-01