feat(core-shared/instrumentation): withSpan returns Instrumented<F>

packages/core-shared/src/instrumentation/with-span.test.ts

@@ -1,6 +1,7 @@
-import { describe, it, expect, vi } from "vitest";
+import { describe, it, expect, expectTypeOf, vi } from "vitest";
 import { withSpan } from "@/instrumentation/with-span";
 import type { ITracer, ISpan, SpanOpts } from "@/instrumentation/tracer.interface";
+import type { Instrumented } from "@/conformance/brands";
 
 function makeRecordingTracer() {
   const calls: SpanOpts[] = [];
@@ -60,3 +61,12 @@ describe("withSpan", () => {
     expect(calls.every((c) => c.name === "test.same")).toBe(true);
   });
 });
+
+describe("withSpan — brand", () => {
+  it("returns an Instrumented<F>", () => {
+    const { tracer } = makeRecordingTracer();
+    const fn = async (a: number) => a + 1;
+    const wrapped = withSpan(tracer, { name: "test.brand", op: "use-case" }, fn);
+    expectTypeOf(wrapped).toMatchTypeOf<Instrumented<typeof fn>>();
+  });
+});