Voice Broadcast playback UI (#9362)

* Implement Voice Broadcast UI

* Update src/voice-broadcast/models/VoiceBroadcastPlayback.ts

Co-authored-by: Travis Ralston <travisr@matrix.org>

Co-authored-by: Travis Ralston <travisr@matrix.org>

test/voice-broadcast/models/VoiceBroadcastPlayback-test.ts

@@ -0,0 +1,116 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { mocked } from "jest-mock";
+import { MatrixEvent } from "matrix-js-sdk/src/matrix";
+
+import {
+    VoiceBroadcastInfoEventType,
+    VoiceBroadcastPlayback,
+    VoiceBroadcastPlaybackEvent,
+    VoiceBroadcastPlaybackState,
+} from "../../../src/voice-broadcast";
+import { mkEvent } from "../../test-utils";
+
+describe("VoiceBroadcastPlayback", () => {
+    const userId = "@user:example.com";
+    const roomId = "!room:example.com";
+    let infoEvent: MatrixEvent;
+    let playback: VoiceBroadcastPlayback;
+    let onStateChanged: (state: VoiceBroadcastPlaybackState) => void;
+
+    const itShouldSetTheStateTo = (state: VoiceBroadcastPlaybackState) => {
+        it(`should set the state to ${state}`, () => {
+            expect(playback.getState()).toBe(state);
+        });
+    };
+
+    const itShouldEmitAStateChangedEvent = (state: VoiceBroadcastPlaybackState) => {
+        it(`should emit a ${state} state changed event`, () => {
+            expect(mocked(onStateChanged)).toHaveBeenCalledWith(state);
+        });
+    };
+
+    beforeAll(() => {
+        infoEvent = mkEvent({
+            event: true,
+            type: VoiceBroadcastInfoEventType,
+            user: userId,
+            room: roomId,
+            content: {},
+        });
+    });
+
+    beforeEach(() => {
+        onStateChanged = jest.fn();
+
+        playback = new VoiceBroadcastPlayback(infoEvent);
+        jest.spyOn(playback, "removeAllListeners");
+        playback.on(VoiceBroadcastPlaybackEvent.StateChanged, onStateChanged);
+    });
+
+    it("should expose the info event", () => {
+        expect(playback.infoEvent).toBe(infoEvent);
+    });
+
+    it("should be in state Stopped", () => {
+        expect(playback.getState()).toBe(VoiceBroadcastPlaybackState.Stopped);
+    });
+
+    describe("when calling start", () => {
+        beforeEach(() => {
+            playback.start();
+        });
+
+        itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);
+
+        describe("and calling toggle", () => {
+            beforeEach(() => {
+                playback.toggle();
+            });
+
+            itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Stopped);
+            itShouldEmitAStateChangedEvent(VoiceBroadcastPlaybackState.Stopped);
+        });
+    });
+
+    describe("when calling stop", () => {
+        beforeEach(() => {
+            playback.stop();
+        });
+
+        itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Stopped);
+
+        describe("and calling toggle", () => {
+            beforeEach(() => {
+                playback.toggle();
+            });
+
+            itShouldSetTheStateTo(VoiceBroadcastPlaybackState.Playing);
+            itShouldEmitAStateChangedEvent(VoiceBroadcastPlaybackState.Stopped);
+        });
+    });
+
+    describe("when calling destroy", () => {
+        beforeEach(() => {
+            playback.destroy();
+        });
+
+        it("should call removeAllListeners", () => {
+            expect(playback.removeAllListeners).toHaveBeenCalled();
+        });
+    });
+});