add more test

src/state/MediaDevices.test.ts

@@ -0,0 +1,59 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { describe, expect, test, vi } from "vitest";
+import { of } from "rxjs";
+
+const getPlatform = vi.hoisted(() => vi.fn(() => "desktop"));
+vi.mock("../Platform", () => ({
+  get platform(): string {
+    return getPlatform();
+  },
+  isFirefox: (): boolean => false,
+}));
+vi.mock("@livekit/components-core", () => ({
+  createMediaDeviceObserver: () => of([]),
+}));
+
+import { AudioOutput, MediaDevices } from "./MediaDevices";
+import { AndroidControlledAudioOutput } from "./AndroidControlledAudioOutput";
+import { IOSControlledAudioOutput } from "./IOSControlledAudioOutput";
+import { ObservableScope } from "./ObservableScope";
+
+// Which audio output implementation is used is decided by what the app hosting
+// Element Call told it, rather than being discovered from the environment.
+describe("MediaDevices audio output", () => {
+  test("uses the browser's own output when nobody else is controlling it", () => {
+    const devices = new MediaDevices(new ObservableScope(), {
+      controlledAudioDevices: false,
+    });
+
+    expect(devices.audioOutput).toBeInstanceOf(AudioOutput);
+  });
+
+  test("hands control to the host on Android", () => {
+    getPlatform.mockReturnValue("android");
+
+    const devices = new MediaDevices(new ObservableScope(), {
+      controlledAudioDevices: true,
+      callIntent: "audio",
+    });
+
+    expect(devices.audioOutput).toBeInstanceOf(AndroidControlledAudioOutput);
+  });
+
+  test("hands control to the host elsewhere too", () => {
+    getPlatform.mockReturnValue("ios");
+
+    const devices = new MediaDevices(new ObservableScope(), {
+      controlledAudioDevices: true,
+      callIntent: "video",
+    });
+
+    expect(devices.audioOutput).toBeInstanceOf(IOSControlledAudioOutput);
+  });
+});