fix(vitest-plugin): prefix walltime URIs of top-level benches with the file path

examples/with-vitest-v3/src/fibonacci.bench.ts

@@ -18,3 +18,7 @@ describe("fibonacci", () => {
     iterativeFibonacci(20);
   });
 });
+
+bench("top-level recursive fibo 15", () => {
+  recursiveFibonacci(15);
+});

examples/with-vitest-v4/src/fibonacci.bench.ts

@@ -18,3 +18,7 @@ describe("fibonacci", () => {
     iterativeFibonacci(20);
   });
 });
+
+bench("top-level recursive fibo 15", () => {
+  recursiveFibonacci(15);
+});

packages/vitest-plugin/src/__tests__/walltime.test.ts

@@ -0,0 +1,114 @@
+import { fromPartial } from "@total-typescript/shoehorn";
+import { describe, expect, it, vi, type RunnerTestSuite } from "vitest";
+import { WalltimeRunner } from "../legacy/walltime";
+
+const coreMocks = vi.hoisted(() => {
+  return {
+    InstrumentHooks: {
+      startBenchmark: vi.fn(),
+      stopBenchmark: vi.fn(),
+      setExecutedBenchmark: vi.fn(),
+      addMarker: vi.fn(),
+      currentTimestamp: vi.fn(() => 0n),
+    },
+    setupCore: vi.fn(),
+  };
+});
+
+vi.mock("@codspeed/core", async (importOriginal) => {
+  const mod = await importOriginal<typeof import("@codspeed/core")>();
+  return { ...mod, ...coreMocks };
+});
+
+console.warn = vi.fn();
+
+// Fully mocked: it loads the Vitest 3/4 runner, absent from the Vitest 5 devDependency.
+vi.mock("../legacy/compat", () => {
+  interface SuiteLike {
+    id: string;
+    type: string;
+    name: string;
+    tasks: SuiteLike[];
+  }
+
+  // Mirrors Vitest's benchmark suite execution: sub-suites run first, then
+  // the suite's own benches run after a `suite-prepare` event for the suite.
+  class NodeBenchmarkRunner {
+    async importTinybench() {
+      return import("tinybench");
+    }
+
+    async runSuite(suite: SuiteLike): Promise<void> {
+      await this.runBenchmarkSuite(suite);
+    }
+
+    private async runBenchmarkSuite(suite: SuiteLike): Promise<void> {
+      for (const task of suite.tasks) {
+        if (task.type === "suite") {
+          await this.runBenchmarkSuite(task);
+        }
+      }
+
+      const benches = suite.tasks.filter((task) => task.type === "test");
+      if (benches.length === 0) {
+        return;
+      }
+
+      await (this as unknown as WalltimeRunner).onTaskUpdate(
+        [],
+        [[suite.id, "suite-prepare", undefined]],
+      );
+      const { Bench } = await this.importTinybench();
+      for (const task of benches) {
+        const bench = new Bench({
+          iterations: 1,
+          time: 0,
+          warmupIterations: 0,
+          warmupTime: 0,
+        });
+        bench.add(task.name, () => {});
+        await bench.run();
+      }
+    }
+  }
+
+  return {
+    NodeBenchmarkRunner,
+    getBenchOptions: vi.fn(),
+  };
+});
+
+const FILE_URI = "packages/vitest-plugin/src/__tests__/walltime.test.ts";
+
+describe("WalltimeRunner", () => {
+  it("prefixes top-level and nested bench URIs with the file path", async () => {
+    const runner = new WalltimeRunner(fromPartial({}));
+    const suite = fromPartial<RunnerTestSuite>({
+      id: "file",
+      type: "suite",
+      file: { filepath: __filename },
+      name: "walltime.test.ts",
+      tasks: [
+        {
+          id: "nested",
+          type: "suite",
+          name: "nested suite",
+          tasks: [
+            { type: "test", name: "nested bench", meta: { benchmark: true } },
+          ],
+        },
+        { type: "test", name: "top-level bench", meta: { benchmark: true } },
+      ],
+    });
+
+    await runner.runSuite(suite);
+
+    const uris = coreMocks.InstrumentHooks.setExecutedBenchmark.mock.calls.map(
+      ([, uri]) => uri,
+    );
+    expect(uris).toEqual([
+      `${FILE_URI}::nested suite::nested bench`,
+      `${FILE_URI}::top-level bench`,
+    ]);
+  });
+});

packages/vitest-plugin/src/legacy/walltime.ts

@@ -51,10 +51,10 @@ export class WalltimeRunner extends NodeBenchmarkRunner {
   private populateBenchmarkUris(suite: RunnerTestSuite, parentPath = ""): void {
     const currentPath =
       parentPath !== "" ? `${parentPath}::${suite.name}` : suite.name;
+    this.suiteUris.set(suite.id, currentPath);
 
     for (const task of suite.tasks) {
       if (task.type === "suite") {
-        this.suiteUris.set(task.id, `${currentPath}::${task.name}`);
         this.populateBenchmarkUris(task, currentPath);
       }
     }