feat(core-shared): add NoopTracer

packages/core-shared/src/instrumentation/noop-tracer.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect, vi } from "vitest";
+import { NoopTracer } from "@/instrumentation/noop-tracer";
+import type { ISpan } from "@/instrumentation/tracer.interface";
+
+describe("NoopTracer", () => {
+  it("startSpan returns the function result", async () => {
+    const tracer = new NoopTracer();
+    const result = await tracer.startSpan({ name: "test.op" }, async () => 42);
+    expect(result).toBe(42);
+  });
+
+  it("startSpan passes a no-op ISpan to the function", async () => {
+    const tracer = new NoopTracer();
+    let received: ISpan | undefined;
+    await tracer.startSpan({ name: "test.op" }, async (span) => {
+      received = span;
+      return undefined;
+    });
+    expect(received).toBeDefined();
+    expect(() => received!.setAttribute("k", "v")).not.toThrow();
+    expect(() => received!.setStatus("ok")).not.toThrow();
+    expect(() => received!.setStatus("error", "msg")).not.toThrow();
+  });
+
+  it("propagates exceptions from the wrapped function", async () => {
+    const tracer = new NoopTracer();
+    const err = new Error("boom");
+    await expect(
+      tracer.startSpan({ name: "test.op" }, async () => {
+        throw err;
+      }),
+    ).rejects.toBe(err);
+  });
+
+  it("does not invoke external services", async () => {
+    const tracer = new NoopTracer();
+    const fn = vi.fn(async () => "ok");
+    await tracer.startSpan({ name: "test.op" }, fn);
+    expect(fn).toHaveBeenCalledTimes(1);
+  });
+});

packages/core-shared/src/instrumentation/noop-tracer.ts

@@ -0,0 +1,12 @@
+import type { ITracer, ISpan, SpanOpts } from "./tracer.interface";
+
+const NOOP_SPAN: ISpan = {
+  setAttribute: () => {},
+  setStatus: () => {},
+};
+
+export class NoopTracer implements ITracer {
+  async startSpan<T>(_opts: SpanOpts, fn: (span: ISpan) => Promise<T>): Promise<T> {
+    return fn(NOOP_SPAN);
+  }
+}