Add calling test that exercises virtual audio

ts/test-mock/bootstrap.ts

@@ -568,6 +568,23 @@ export class Bootstrap {
     await fs.writeFile(path.join(outDir, `screenshot-${id}.png`), screenshot);
   }
 
+  public async screenshotWindow(
+    window: Page,
+    testName?: string
+  ): Promise<void> {
+    const outDir = await this.#getArtifactsDir(testName);
+    if (outDir == null) {
+      return;
+    }
+
+    const screenshot = await window.screenshot();
+
+    const id = this.#screenshotId;
+    this.#screenshotId += 1;
+
+    await fs.writeFile(path.join(outDir, `screenshot-${id}.png`), screenshot);
+  }
+
   public async saveLogs(
     app: App | undefined = this.#lastApp,
     testName?: string