chore: Upgrade to Vitest 4 and regroup tests for performance (#2618)

package.json

@@ -68,7 +68,7 @@
     "@types/masonry-layout": "^4.2.8",
     "@typescript-eslint/eslint-plugin": "^8.30.1",
     "@typescript-eslint/parser": "^8.30.1",
-    "@vitest/coverage-istanbul": "^1.6.0",
+    "@vitest/coverage-istanbul": "^4.1.10",
     "conventional-changelog-conventionalcommits": "^8.0.0",
     "docsify-cli": "^4.4.4",
     "eslint": "^9.24.0",
@@ -86,8 +86,8 @@
     "semantic-release-export-data": "^1.1.0",
     "type-fest": "^4.41.0",
     "typescript": "^5.8.3",
-    "vitest": "^1.6.0",
+    "vitest": "^4.1.10",
-    "vitest-mock-extended": "^1.3.1"
+    "vitest-mock-extended": "^5.1.0"
   },
   "release": {
     "branches": [
@@ -188,7 +188,7 @@
     "format-check": "prettier --check .",
     "rollup": "rollup -c",
     "prune": "knip",
-    "test": "VITEST_GROUP=shared vitest run && VITEST_GROUP=isolated vitest run",
+    "test": "vitest run",
     "coverage": "vitest run --coverage"
   },
   "volta": {

src/card-controller/camera-triggers-manager.ts

@@ -242,14 +242,14 @@ export class CameraTriggersManager {
       } else if (ev.fidelity === 'high' && triggerAction === 'media') {
         // Choose the most appropriate media view based on what's available.
         // Priority: review > clip > snapshot
+        /* istanbul ignore next: the `null` case is unreachable due to `skipViewAction` above -- @preserve */
         const view = ev.review
           ? 'review'
           : ev.clip
             ? 'clip'
             : ev.snapshot
               ? 'snapshot'
-              : /* istanbul ignore next: unreachable due to `skipViewAction` above -- @preserve */
+              : null;
-                null;
 
         /* istanbul ignore next: unreachable due to `skipViewAction` above -- @preserve */
         if (view) {

src/components-lib/media-height-controller.ts

@@ -101,11 +101,10 @@ export class MediaHeightController {
   }
 
   private _initializeRoot(): void {
+    /* istanbul ignore next: the absent-root path cannot be reached as root will
+    always exist by the time the mutation observer is observing -- @preserve */
     const children = [
-      ...(this._root?.querySelectorAll<HTMLElement>(this._selector) ??
+      ...(this._root?.querySelectorAll<HTMLElement>(this._selector) ?? []),
-        /* istanbul ignore next: this path cannot be reached as root will always
-        exist by the time the mutation observer is observing -- @preserve */
-        []),
     ];
     if (isEqual(children, this._children)) {
       return;

src/components-lib/zoom/zoom-controller.ts

@@ -123,6 +123,12 @@ export class ZoomController {
       config?.zoom ?? ZOOM_DEFAULT_SCALE,
     );
 
+    // The ZOOM_DEFAULT_SCALE fallback is not reachable: without a zoom value a
+    // default of 1 is assumed in _convertPercentToXYPan, which returns null at
+    // the default zoom, leaving `converted` unset.
+    /* istanbul ignore next @preserve */
+    const startScale = config?.zoom ?? ZOOM_DEFAULT_SCALE;
+
     this._panzoom = Panzoom(this._element, {
       contain: 'outside',
       maxScale: 10,
@@ -140,16 +146,7 @@ export class ZoomController {
       // Set the initial pan/zoom values to avoid an initial unzoomed view.
       ...(config && converted && { startX: converted.x }),
       ...(config && converted && { startY: converted.y }),
-      ...(config &&
+      ...(config && converted && { startScale }),
-        converted && {
-          startScale:
-            config.zoom ??
-            // This is not reachable as without a zoom value, a default of 1 is
-            // assumed in _convertPercentToXYPan, which will return null @
-            // default zoom, and so this cannot be reached in practice.
-            /* istanbul ignore next @preserve */
-            ZOOM_DEFAULT_SCALE,
-        }),
     });
 
     const registerListeners = (
@@ -436,18 +433,16 @@ export class ZoomController {
       return true;
     }
 
+    // The ZOOM_DEFAULT_SCALE fallback cannot be reached: when
+    // this._defaultSettings.zoom is undefined, convertedDefault ends up null
+    // above and this function has already returned.
+    /* istanbul ignore next @preserve */
+    const defaultScale = this._defaultSettings.zoom ?? ZOOM_DEFAULT_SCALE;
+
     return (
       arefloatsApproximatelyEqual(x, convertedDefault.x) &&
       arefloatsApproximatelyEqual(y, convertedDefault.y) &&
-      arefloatsApproximatelyEqual(
+      arefloatsApproximatelyEqual(scale, defaultScale)
-        scale,
-        this._defaultSettings.zoom ??
-          // The ZOOM_DEFAULT_SCALE clause below cannot be reached since when
-          // this._defaultConfig.zoom is undefined, convertedDefault will end up
-          // null above and this function will have already returned.
-          /* istanbul ignore next @preserve */
-          ZOOM_DEFAULT_SCALE,
-      )
     );
   }
 

tests/camera-manager/frigate/engine-frigate.test.ts

@@ -208,6 +208,7 @@ describe('FrigateQueryResultsClassifier', () => {
 describe('FrigateCameraManagerEngine', () => {
   afterEach(() => {
     vi.restoreAllMocks();
+    vi.clearAllMocks();
   });
 
   describe('getEngineType', () => {

tests/card-controller/actions/actions/set.test.ts

@@ -1,4 +1,4 @@
-import { describe, expect, it, vi } from 'vitest';
+import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { ActionSet } from '../../../../src/card-controller/actions/actions/set';
 import { createLogAction } from '../../../../src/utils/action';
@@ -6,6 +6,10 @@ import { arrayify } from '../../../../src/utils/basic';
 import { createCardAPI } from '../../../test-utils';
 
 describe('ActionSet', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
   const createAPI = () => {
     const api = createCardAPI();
     vi.mocked(api.getLockManager().getAllowedActions).mockImplementation((actions) =>

tests/card-controller/call/manager.test.ts

@@ -29,9 +29,13 @@ import {
 
 // Replace Ringtone with a fresh `mock<Ringtone>()` per construction so each
 // CallManager gets an isolated, type-safe ringtone we can assert on. The
-// real Ringtone creates an AudioContext, which we never want in tests.
+// real Ringtone creates an AudioContext, which we never want in tests. The
+// implementation must be callable with `new`, so it cannot be an arrow
+// function.
 vi.mock('../../../src/card-controller/call/ringtone', () => ({
-  Ringtone: vi.fn().mockImplementation(() => mock<Ringtone>()),
+  Ringtone: vi.fn().mockImplementation(function () {
+    return mock<Ringtone>();
+  }),
 }));
 
 // Each test creates a new CallManager which constructs a new Ringtone, so the

tests/card-controller/call/ringtone.test.ts

@@ -12,20 +12,32 @@ import type { RingtoneConfig } from '../../../src/config/schema/live';
 // Each tone constructor returns a fresh `mock<>()` per `new` call; the mock
 // implementation persists across `vi.clearAllMocks()` (which only clears call
 // records, not implementations) so tests don't need per-test re-installation.
+// The implementations must be callable with `new`, so they cannot be arrow
+// functions.
 vi.mock('../../../src/card-controller/call/tones/chime', () => ({
-  ChimeTone: vi.fn().mockImplementation(() => mock<ChimeTone>()),
+  ChimeTone: vi.fn().mockImplementation(function () {
+    return mock<ChimeTone>();
+  }),
 }));
 vi.mock('../../../src/card-controller/call/tones/westminster', () => ({
-  WestminsterTone: vi.fn().mockImplementation(() => mock<WestminsterTone>()),
+  WestminsterTone: vi.fn().mockImplementation(function () {
+    return mock<WestminsterTone>();
+  }),
 }));
 vi.mock('../../../src/card-controller/call/tones/arpeggio', () => ({
-  ArpeggioTone: vi.fn().mockImplementation(() => mock<ArpeggioTone>()),
+  ArpeggioTone: vi.fn().mockImplementation(function () {
+    return mock<ArpeggioTone>();
+  }),
 }));
 vi.mock('../../../src/card-controller/call/tones/melody', () => ({
-  MelodyTone: vi.fn().mockImplementation(() => mock<MelodyTone>()),
+  MelodyTone: vi.fn().mockImplementation(function () {
+    return mock<MelodyTone>();
+  }),
 }));
 vi.mock('../../../src/card-controller/call/tones/custom', () => ({
-  CustomTone: vi.fn().mockImplementation(() => mock<CustomTone>()),
+  CustomTone: vi.fn().mockImplementation(function () {
+    return mock<CustomTone>();
+  }),
 }));
 
 // Returns the most recently constructed instance of a mocked class.
@@ -187,7 +199,7 @@ describe('lock', () => {
 describe('natural finish', () => {
   it('should release the lock when the tone fires its finished handler', () => {
     let finishedHandler: (() => void) | undefined;
-    vi.mocked(ChimeTone).mockImplementationOnce(() => {
+    vi.mocked(ChimeTone).mockImplementationOnce(function () {
       const tone = mock<ChimeTone>();
       vi.mocked(tone.start).mockImplementation((handler) => {
         finishedHandler = handler;

tests/card-controller/call/tones/custom.test.ts

@@ -8,7 +8,7 @@ interface AudioMocks {
   // and pushed here in construction order, so tests can dispatch real events
   // and read real properties (`loop`, `currentTime`, etc.) on the instances.
   instances: HTMLAudioElement[];
-  ctor: Mock<[string?], HTMLAudioElement>;
+  ctor: Mock<(url?: string) => HTMLAudioElement>;
 }
 
 // Uses real jsdom HTMLAudioElement instances and only stubs the parts jsdom
@@ -33,7 +33,10 @@ const useAudioElementMocks = (): AudioMocks => {
     vi.spyOn(HTMLMediaElement.prototype, 'pause').mockImplementation(() => {});
 
     const RealAudio = window.Audio;
-    handle.ctor = vi.fn((url?: string) => {
+
+    // The source calls `new Audio(...)`, and a mock implementation must be
+    // callable with `new`, so it cannot be an arrow function.
+    handle.ctor = vi.fn(function (url?: string) {
       const audio = new RealAudio(url);
       handle.instances.push(audio);
       return audio;

tests/card-controller/call/tones/test-utils.ts

@@ -10,7 +10,7 @@ import { mock, type MockProxy } from 'vitest-mock-extended';
 // over the same observable state.
 interface AudioMocks {
   audioContext: MockProxy<AudioContext>;
-  audioContextCtor: Mock<[], MockProxy<AudioContext>>;
+  audioContextCtor: Mock<() => MockProxy<AudioContext>>;
 
   // Filled in the order `createOscillator()` / `createGain()` were called.
   oscillators: MockProxy<OscillatorNode>[];
@@ -73,7 +73,11 @@ export const useAudioMocks = (): AudioMocks => {
       configurable: true,
     });
 
-    audio.audioContextCtor = vi.fn(() => audio.audioContext);
+    // The source calls `new AudioContext()`, and a mock implementation must be
+    // callable with `new`, so it cannot be an arrow function.
+    audio.audioContextCtor = vi.fn(function () {
+      return audio.audioContext;
+    });
     vi.stubGlobal('AudioContext', audio.audioContextCtor);
   });
 

tests/card-controller/effects/effects-manager.test.ts

@@ -5,28 +5,43 @@ import type { EffectComponent } from '../../../src/card-controller/effects/types
 import type { EffectName } from '../../../src/types';
 import { flushPromises } from '../../test-utils';
 
+// The source constructs each effect component with `new`, and a mock
+// implementation must be callable with `new`, so it cannot be an arrow
+// function.
 vi.mock('../../../src/components/effects/fireworks', () => ({
-  AdvancedCameraCardEffectFireworks: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectFireworks: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 vi.mock('../../../src/components/effects/check', () => ({
-  AdvancedCameraCardEffectCheck: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectCheck: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 vi.mock('../../../src/components/effects/ghost', () => ({
-  AdvancedCameraCardEffectGhost: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectGhost: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 vi.mock('../../../src/components/effects/hearts', () => ({
-  AdvancedCameraCardEffectHearts: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectHearts: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 vi.mock('../../../src/components/effects/shamrocks', () => ({
-  AdvancedCameraCardEffectShamrocks: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectShamrocks: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 vi.mock('../../../src/components/effects/snow', () => ({
-  AdvancedCameraCardEffectSnow: vi.fn(() => createMockEffectComponent()),
+  AdvancedCameraCardEffectSnow: vi.fn(function () {
+    return createMockEffectComponent();
+  }),
 }));
 
 const createMockEffectComponent = (): EffectComponent => {

tests/card-controller/fullscreen/fullscreen-manager.test.ts

@@ -11,6 +11,7 @@ vi.mock('../../../src/card-controller/fullscreen/factory');
 describe('FullscreenManager', () => {
   afterEach(() => {
     vi.restoreAllMocks();
+    vi.clearAllMocks();
   });
 
   it('should initialize', () => {

tests/card-controller/fullscreen/screenfull/index.test.ts

@@ -29,6 +29,7 @@ describe('ScreenfullFullScreenProvider', () => {
 
   afterEach(() => {
     vi.restoreAllMocks();
+    vi.clearAllMocks();
   });
 
   describe('should connect', () => {

tests/components-lib/lazy-load-controller.test.ts

@@ -35,11 +35,13 @@ describe('LazyLoadController', () => {
     Object.defineProperty(document, 'visibilityState', {
       value: 'visible',
       writable: true,
+      configurable: true,
     });
   });
 
   afterEach(() => {
     vi.restoreAllMocks();
+    vi.clearAllMocks();
   });
 
   it('should be unloaded by default', () => {
@@ -281,6 +283,7 @@ describe('LazyLoadController', () => {
       Object.defineProperty(document, 'visibilityState', {
         value: 'hidden',
         writable: true,
+        configurable: true,
       });
 
       const controller = new LazyLoadController(createLitElement());

tests/components-lib/live/providers/go2rtc-experimental/adapters/media-source.test.ts

@@ -7,7 +7,7 @@ class FakeMediaSource extends EventTarget {
 
   public addSourceBuffer = vi.fn();
   public setLiveSeekableRange = vi.fn();
-  public static isTypeSupported = vi.fn<[string], boolean>(() => true);
+  public static isTypeSupported = vi.fn<(mimeType: string) => boolean>(() => true);
 
   constructor() {
     super();
@@ -19,7 +19,7 @@ class FakeManagedMediaSource extends EventTarget {
   public addSourceBuffer = vi.fn();
   public setLiveSeekableRange = vi.fn();
   public readyState: 'closed' | 'open' | 'ended' = 'closed';
-  public static isTypeSupported = vi.fn<[string], boolean>(() => true);
+  public static isTypeSupported = vi.fn<(mimeType: string) => boolean>(() => true);
 }
 
 const createObjectURL = vi.fn(() => 'blob:fake-url');

tests/components-lib/live/providers/go2rtc-experimental/session-controller.test.ts

@@ -100,7 +100,7 @@ describe('Go2RTCSessionController', () => {
     cardWideConfig?: CardWideConfig | null;
   }) => {
     const websockets: FakeWebSocket[] = [];
-    const createWebSocket = vi.fn<[string], WebSocket>(() => {
+    const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
       const websocket = new FakeWebSocket();
       websockets.push(websocket);
       return websocket.asWebSocket();
@@ -1060,7 +1060,7 @@ describe('Go2RTCSessionController', () => {
 
     it('should ignore callbacks fired while a binary source is constructed', () => {
       const websockets: FakeWebSocket[] = [];
-      const createWebSocket = vi.fn<[string], WebSocket>(() => {
+      const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
         const websocket = new FakeWebSocket();
         websockets.push(websocket);
         return websocket.asWebSocket();
@@ -1095,7 +1095,7 @@ describe('Go2RTCSessionController', () => {
 
     it('should ignore callbacks fired while a WebRTC source is constructed', () => {
       const websockets: FakeWebSocket[] = [];
-      const createWebSocket = vi.fn<[string], WebSocket>(() => {
+      const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
         const websocket = new FakeWebSocket();
         websockets.push(websocket);
         return websocket.asWebSocket();
@@ -1129,7 +1129,7 @@ describe('Go2RTCSessionController', () => {
 
     it('should use the default binary source factory when none is injected', () => {
       const websockets: FakeWebSocket[] = [];
-      const createWebSocket = vi.fn<[string], WebSocket>(() => {
+      const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
         const websocket = new FakeWebSocket();
         websockets.push(websocket);
         return websocket.asWebSocket();
@@ -1160,7 +1160,7 @@ describe('Go2RTCSessionController', () => {
     it('should use the default WebRTC source factory when none is injected', () => {
       vi.stubGlobal('RTCPeerConnection', FakeRTCPeerConnection);
       const websockets: FakeWebSocket[] = [];
-      const createWebSocket = vi.fn<[string], WebSocket>(() => {
+      const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
         const websocket = new FakeWebSocket();
         websockets.push(websocket);
         return websocket.asWebSocket();
@@ -1187,7 +1187,7 @@ describe('Go2RTCSessionController', () => {
 
     it('should create an off-screen video with the default factory when none is injected', () => {
       const websockets: FakeWebSocket[] = [];
-      const createWebSocket = vi.fn<[string], WebSocket>(() => {
+      const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
         const websocket = new FakeWebSocket();
         websockets.push(websocket);
         return websocket.asWebSocket();

tests/components-lib/live/providers/go2rtc-experimental/signaling.test.ts

@@ -9,7 +9,7 @@ describe('SignalingChannel', () => {
     disconnectCallback?: () => void;
   }) => {
     const websockets: FakeWebSocket[] = [];
-    const createWebSocket = vi.fn<[string], WebSocket>(() => {
+    const createWebSocket = vi.fn<(url: string) => WebSocket>(() => {
       const websocket = new FakeWebSocket();
       websockets.push(websocket);
       return websocket.asWebSocket();
@@ -238,7 +238,11 @@ describe('SignalingChannel', () => {
   });
 
   it('should construct a real websocket by default', () => {
-    const webSocketConstructor = vi.fn(() => new FakeWebSocket().asWebSocket());
+    // A mock implementation must be callable with `new`, so it cannot be an
+    // arrow function.
+    const webSocketConstructor = vi.fn(function () {
+      return new FakeWebSocket().asWebSocket();
+    });
     vi.stubGlobal('WebSocket', webSocketConstructor);
     const channel = new SignalingChannel('ws://host/api/ws', {});
     channel.connect();

tests/components-lib/live/providers/go2rtc-experimental/sources/mjpeg.test.ts

@@ -14,7 +14,7 @@ describe('MJPEGStreamSource', () => {
     const channel = new FakeStreamSourceChannel();
     const loadedCallback = vi.fn();
     const failedCallback = vi.fn();
-    const showFrame = vi.fn<[Blob], Promise<void>>(() => Promise.resolve());
+    const showFrame = vi.fn<(blob: Blob) => Promise<void>>(() => Promise.resolve());
 
     const context: StreamSourceContext<ImageStreamTarget> = {
       target: { kind: 'image', showFrame },

tests/components-lib/live/providers/go2rtc-experimental/sources/mp4.test.ts

@@ -32,7 +32,7 @@ describe('MP4StreamSource', () => {
     const channel = new FakeStreamSourceChannel();
     const loadedCallback = vi.fn();
     const failedCallback = vi.fn();
-    const showFrame = vi.fn<[Blob], Promise<void>>(() => Promise.resolve());
+    const showFrame = vi.fn<(blob: Blob) => Promise<void>>(() => Promise.resolve());
     const context: StreamSourceContext<ImageStreamTarget> = {
       target: { kind: 'image', showFrame },
       channel,
@@ -65,6 +65,7 @@ describe('MP4StreamSource', () => {
 
   afterEach(() => {
     vi.useRealTimers();
+    vi.restoreAllMocks();
   });
 
   it('should request the mp4 stream on start', () => {
@@ -217,6 +218,12 @@ describe('MP4StreamSource', () => {
       callbacks: { loadedCallback: vi.fn(), failedCallback: vi.fn() },
     });
 
+    // This is the only test that reaches a real canvas element. jsdom does not
+    // implement `getContext` and writes an error to the console when it is
+    // called; the source treats a missing context as nothing to draw to avoid
+    // console spam.
+    vi.spyOn(HTMLCanvasElement.prototype, 'getContext').mockReturnValue(null);
+
     const createElement = vi.spyOn(document, 'createElement');
     source.start();
     channel.binaryCallback?.(frame());

tests/components-lib/live/providers/go2rtc-experimental/test-utils.ts

@@ -125,7 +125,7 @@ class FakeRTCTransceiver {
   public currentDirection: string;
   public sender: {
     track: FakeMediaStreamTrack | null;
-    replaceTrack: Mock<[MediaStreamTrack | null], Promise<void>>;
+    replaceTrack: Mock<(track: MediaStreamTrack | null) => Promise<void>>;
   };
   public receiver: { track: FakeMediaStreamTrack };
 
@@ -134,7 +134,7 @@ class FakeRTCTransceiver {
     this.currentDirection = direction;
     this.sender = {
       track,
-      replaceTrack: vi.fn<[MediaStreamTrack | null], Promise<void>>(() =>
+      replaceTrack: vi.fn<(track: MediaStreamTrack | null) => Promise<void>>(() =>
         Promise.resolve(),
       ),
     };
@@ -241,9 +241,9 @@ export class FakeMediaSourceInstance implements MediaSourceInterface {
   public attach = vi.fn();
   public detach = vi.fn();
   public setLiveSeekableRange = vi.fn();
-  public isOpen = vi.fn<[], boolean>(() => true);
+  public isOpen = vi.fn<() => boolean>(() => true);
-  public isTypeSupported = vi.fn<[string], boolean>(() => true);
+  public isTypeSupported = vi.fn<(mimeType: string) => boolean>(() => true);
-  public addSourceBuffer = vi.fn<[string], SourceBuffer>(() =>
+  public addSourceBuffer = vi.fn<(mimeType: string) => SourceBuffer>(() =>
     this.sourceBuffer.asSourceBuffer(),
   );
 

tests/components-lib/media-grid-controller.test.ts

@@ -24,8 +24,10 @@ vi.mock('lodash-es', async () => ({
 }));
 
 const masonry = mock<ExtendedMasonry>();
+// The source calls `new Masonry(...)`, and a mock implementation must be
+// callable with `new`, so it cannot be an arrow function.
 vi.mock('masonry-layout', () => ({
-  default: vi.fn().mockImplementation(() => {
+  default: vi.fn().mockImplementation(function () {
     return masonry;
   }),
 }));

tests/components-lib/signed-url-controller.test.ts

@@ -23,6 +23,7 @@ const createEndpoint = (url: string, sign?: boolean): Endpoint => ({
 describe('SignedURLController', () => {
   afterEach(() => {
     vi.restoreAllMocks();
+    vi.clearAllMocks();
   });
 
   it('should initialize correctly', () => {

tests/components-lib/zoom/zoom-controller.test.ts

@@ -2,7 +2,7 @@ import Panzoom, {
   type PanzoomEventDetail,
   type PanzoomObject,
 } from '@dermotduffy/panzoom';
-import { beforeAll, beforeEach, describe, expect, it, vi } from 'vitest';
+import { beforeAll, beforeEach, describe, expect, it, vi, type Mock } from 'vitest';
 import { mock, mockClear } from 'vitest-mock-extended';
 
 import { ZoomController } from '../../../src/components-lib/zoom/zoom-controller';
@@ -11,6 +11,7 @@ import {
   createTouchEvent,
   requestAnimationFrameMock,
   ResizeObserverMock,
+  stubMatchMedia,
 } from '../../test-utils';
 
 vi.mock('@dermotduffy/panzoom');
@@ -37,7 +38,7 @@ const setElementToDefaultCardSize = (element: HTMLElement, multiple?: number): v
 
 // @vitest-environment jsdom
 describe('ZoomController', () => {
-  const mediaSpy = vi.spyOn(window, 'matchMedia');
+  let mediaSpy: Mock;
 
   const createMockPanZoom = (): PanzoomObject => {
     const panzoom = mock<PanzoomObject>();
@@ -60,6 +61,7 @@ describe('ZoomController', () => {
   beforeEach(() => {
     vi.mocked(Panzoom).mockReset();
     vi.mocked(global.ResizeObserver).mockClear();
+    mediaSpy = stubMatchMedia();
     mediaSpy.mockReturnValue(<MediaQueryList>{ matches: true });
   });
 

tests/condition-trigger/common/media-query-watcher.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { MediaQueryWatcher } from '../../../src/condition-trigger/common/media-query-watcher';
+import { stubMatchMedia } from '../../test-utils';
 
 // @vitest-environment jsdom
 describe('MediaQueryWatcher', () => {
@@ -9,7 +10,7 @@ describe('MediaQueryWatcher', () => {
   });
 
   it('should report whether the query matches', () => {
-    vi.spyOn(window, 'matchMedia').mockReturnValue({
+    stubMatchMedia().mockReturnValue({
       matches: true,
     } as unknown as MediaQueryList);
 
@@ -18,7 +19,7 @@ describe('MediaQueryWatcher', () => {
 
   it('should invoke the callback on a media-query change', () => {
     const addEventListener = vi.fn();
-    vi.spyOn(window, 'matchMedia').mockReturnValue({
+    stubMatchMedia().mockReturnValue({
       addEventListener,
       removeEventListener: vi.fn(),
     } as unknown as MediaQueryList);
@@ -35,7 +36,7 @@ describe('MediaQueryWatcher', () => {
   it('should stop listening and ignore changes after teardown', () => {
     const addEventListener = vi.fn();
     const removeEventListener = vi.fn();
-    vi.spyOn(window, 'matchMedia').mockReturnValue({
+    stubMatchMedia().mockReturnValue({
       addEventListener,
       removeEventListener,
     } as unknown as MediaQueryList);

tests/condition-trigger/conditions/conditions-manager.test.ts

@@ -8,6 +8,7 @@ import {
   createMockTemplateRenderer,
   createStateEntity,
   stubConnectedHomeAssistant,
+  stubMatchMedia,
 } from '../../test-utils';
 
 // A mock renderer for the orchestration tests, which never render templates.
@@ -71,7 +72,7 @@ describe('ConditionsManager', () => {
   it('should re-evaluate and notify when a subscribed condition source changes', () => {
     const addEventListener = vi.fn();
     const removeEventListener = vi.fn();
-    vi.spyOn(window, 'matchMedia')
+    stubMatchMedia()
       .mockReturnValueOnce({
         addEventListener: addEventListener,
         removeEventListener: removeEventListener,

tests/condition-trigger/conditions/conditions/screen.test.ts

@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { createConditionEvaluator } from '../../../../src/condition-trigger/conditions/factory';
+import { stubMatchMedia } from '../../../test-utils';
 import { createEvaluatorContext } from './test-utils';
 
 // @vitest-environment jsdom
@@ -10,7 +11,7 @@ describe('screen condition', () => {
   });
 
   it('should evaluate the media query', () => {
-    vi.spyOn(window, 'matchMedia').mockReturnValue({
+    stubMatchMedia().mockReturnValue({
       matches: true,
     } as unknown as MediaQueryList);
 
@@ -30,7 +31,7 @@ describe('screen condition', () => {
   });
 
   it('should not match or expose a source without a media query', () => {
-    const matchMedia = vi.spyOn(window, 'matchMedia');
+    const matchMedia = stubMatchMedia();
     const evaluator = createConditionEvaluator(
       { condition: 'screen' as const },
       createEvaluatorContext(),

tests/condition-trigger/triggers/triggers/screen.test.ts

@@ -2,6 +2,7 @@ import { afterEach, describe, expect, it, vi, type Mock } from 'vitest';
 
 import { ScreenTrigger } from '../../../../src/condition-trigger/triggers/triggers/screen';
 import type { TriggerOfType } from '../../../../src/condition-trigger/triggers/triggers/types';
+import { stubMatchMedia } from '../../../test-utils';
 
 // @vitest-environment jsdom
 describe('ScreenTrigger', () => {
@@ -10,7 +11,7 @@ describe('ScreenTrigger', () => {
   const removeEventListener = vi.fn();
 
   const mockMatchMedia = (): void => {
-    vi.spyOn(window, 'matchMedia').mockImplementation(
+    stubMatchMedia().mockImplementation(
       () =>
         ({
           get matches(): boolean {

tests/config/profiles/casting.test.ts

@@ -1,5 +1,6 @@
 import { expect, it } from 'vitest';
 
+import { copyConfig } from '../../../src/config/management';
 import { CASTING_PROFILE } from '../../../src/config/profiles/casting';
 import { setProfiles } from '../../../src/config/profiles/set-profiles';
 import { advancedCameraCardConfigSchema } from '../../../src/config/schema/types';
@@ -23,7 +24,10 @@ it('should contain expected defaults', () => {
 
 it('should be parseable after application', () => {
   const rawInputConfig = createRawConfig();
-  const parsedConfig = advancedCameraCardConfigSchema.parse(rawInputConfig);
+  // `setProfiles` writes into the config it is given, and Zod hands out a
+  // single shared instance of each default object, so the parse result must be
+  // cloned before it is mutated.
+  const parsedConfig = copyConfig(advancedCameraCardConfigSchema.parse(rawInputConfig));
 
   setProfiles(rawInputConfig, parsedConfig, ['casting']);
 

tests/config/profiles/doorbell.test.ts

@@ -1,5 +1,6 @@
 import { expect, it } from 'vitest';
 
+import { copyConfig } from '../../../src/config/management';
 import { DOORBELL_PROFILE } from '../../../src/config/profiles/doorbell';
 import { setProfiles } from '../../../src/config/profiles/set-profiles';
 import { advancedCameraCardConfigSchema } from '../../../src/config/schema/types';
@@ -17,7 +18,10 @@ it('should contain expected defaults', () => {
 
 it('should be parseable after application', () => {
   const rawInputConfig = createRawConfig();
-  const parsedConfig = advancedCameraCardConfigSchema.parse(rawInputConfig);
+  // `setProfiles` writes into the config it is given, and Zod hands out a
+  // single shared instance of each default object, so the parse result must be
+  // cloned before it is mutated.
+  const parsedConfig = copyConfig(advancedCameraCardConfigSchema.parse(rawInputConfig));
 
   setProfiles(rawInputConfig, parsedConfig, ['doorbell']);
 

tests/config/profiles/low-performance.test.ts

@@ -1,5 +1,6 @@
 import { expect, it } from 'vitest';
 
+import { copyConfig } from '../../../src/config/management';
 import { LOW_PERFORMANCE_PROFILE } from '../../../src/config/profiles/low-performance';
 import { setProfiles } from '../../../src/config/profiles/set-profiles';
 import { advancedCameraCardConfigSchema } from '../../../src/config/schema/types';
@@ -53,7 +54,10 @@ it('should contain expected defaults', () => {
 
 it('should be parseable after application', () => {
   const rawInputConfig = createRawConfig();
-  const parsedConfig = advancedCameraCardConfigSchema.parse(rawInputConfig);
+  // `setProfiles` writes into the config it is given, and Zod hands out a
+  // single shared instance of each default object, so the parse result must be
+  // cloned before it is mutated.
+  const parsedConfig = copyConfig(advancedCameraCardConfigSchema.parse(rawInputConfig));
 
   setProfiles(rawInputConfig, parsedConfig, ['low-performance']);
 

tests/config/profiles/scrubbing.test.ts

@@ -1,5 +1,6 @@
 import { expect, it } from 'vitest';
 
+import { copyConfig } from '../../../src/config/management';
 import { SCRUBBING_PROFILE } from '../../../src/config/profiles/scrubbing';
 import { setProfiles } from '../../../src/config/profiles/set-profiles';
 import { advancedCameraCardConfigSchema } from '../../../src/config/schema/types';
@@ -18,7 +19,10 @@ it('should contain expected defaults', () => {
 
 it('should be parseable after application', () => {
   const rawInputConfig = createRawConfig();
-  const parsedConfig = advancedCameraCardConfigSchema.parse(rawInputConfig);
+  // `setProfiles` writes into the config it is given, and Zod hands out a
+  // single shared instance of each default object, so the parse result must be
+  // cloned before it is mutated.
+  const parsedConfig = copyConfig(advancedCameraCardConfigSchema.parse(rawInputConfig));
 
   setProfiles(rawInputConfig, parsedConfig, ['low-performance']);
 

tests/test-utils.ts

@@ -6,7 +6,7 @@ import {
 } from 'home-assistant-js-websocket';
 import type { LitElement } from 'lit';
 import screenfull from 'screenfull';
-import { expect, vi } from 'vitest';
+import { expect, onTestFinished, vi, type Mock } from 'vitest';
 import { mock } from 'vitest-mock-extended';
 
 import { Camera } from '../src/camera-manager/camera';
@@ -577,23 +577,35 @@ export class TestViewMedia extends ViewMedia implements EventViewMedia, ReviewVi
   }
 }
 
-export const ResizeObserverMock = vi.fn(() => ({
+// jsdom does not implement `window.matchMedia`, so it has to be installed
-  disconnect: vi.fn(),
+// before a test can control what it returns. Must be called from inside a test
-  observe: vi.fn(),
+// or a test hook, as the stub is removed once the test finishes.
-  unobserve: vi.fn(),
+export const stubMatchMedia = (): Mock => {
-}));
+  const matchMedia = vi.fn();
+  vi.stubGlobal('matchMedia', matchMedia);
+  onTestFinished(() => {
+    // There is no singular unstubGlobal.
+    Reflect.deleteProperty(globalThis, 'matchMedia');
+  });
+  return matchMedia;
+};
 
-export const IntersectionObserverMock = vi.fn(() => ({
+// A mock implementation must be callable with `new`, so it cannot be an arrow
-  disconnect: vi.fn(),
+// function.
-  observe: vi.fn(),
+const createObserverMock = () =>
-  unobserve: vi.fn(),
+  vi.fn(function () {
-}));
+    return {
+      disconnect: vi.fn(),
+      observe: vi.fn(),
+      unobserve: vi.fn(),
+    };
+  });
 
-export const MutationObserverMock = vi.fn(() => ({
+export const ResizeObserverMock = createObserverMock();
-  disconnect: vi.fn(),
+
-  observe: vi.fn(),
+export const IntersectionObserverMock = createObserverMock();
-  unobserve: vi.fn(),
+
-}));
+export const MutationObserverMock = createObserverMock();
 
 export const requestAnimationFrameMock = (callback: FrameRequestCallback) => {
   callback(new Date().getTime());
@@ -650,6 +662,7 @@ export const callVisibilityHandler = async (visible: boolean): Promise<void> =>
   Object.defineProperty(document, 'visibilityState', {
     value: visible ? 'visible' : 'hidden',
     writable: true,
+    configurable: true,
   });
 
   const mock = vi.mocked(global.document.addEventListener).mock;

tests/utils/basic.test.ts

@@ -32,7 +32,7 @@ import {
   setOrRemoveAttribute,
   setOrRemoveStyleProperty,
 } from '../../src/utils/basic.js';
-import { createSlot, createSlotHost } from '../test-utils.js';
+import { createSlot, createSlotHost, stubMatchMedia } from '../test-utils.js';
 
 describe('prettifyTitle', () => {
   it('should return undefined when passed undefined', () => {
@@ -146,11 +146,11 @@ describe('isHoverableDevice', () => {
   });
 
   it('should return hoverable', () => {
-    vi.spyOn(window, 'matchMedia').mockReturnValue(<MediaQueryList>{ matches: true });
+    stubMatchMedia().mockReturnValue(<MediaQueryList>{ matches: true });
     expect(isHoverableDevice()).toBeTruthy();
   });
   it('should return not hoverable', () => {
-    vi.spyOn(window, 'matchMedia').mockReturnValue(<MediaQueryList>{ matches: false });
+    stubMatchMedia().mockReturnValue(<MediaQueryList>{ matches: false });
     expect(isHoverableDevice()).toBeFalsy();
   });
 });

tests/utils/thumbnail.test.ts

@@ -71,7 +71,11 @@ describe('thumbnail utilities', () => {
     });
     vi.stubGlobal(
       'FileReader',
-      vi.fn(() => mockFileReader),
+      // The source calls `new FileReader()`, and a mock implementation must be
+      // callable with `new`, so it cannot be an arrow function.
+      vi.fn(function () {
+        return mockFileReader;
+      }),
     );
 
     createFetchThumbnailTask(
@@ -129,7 +133,9 @@ describe('thumbnail utilities', () => {
     const mockFileReader = mock<FileReader>();
     vi.stubGlobal(
       'FileReader',
-      vi.fn(() => mockFileReader),
+      vi.fn(function () {
+        return mockFileReader;
+      }),
     );
 
     createFetchThumbnailTask(
@@ -166,7 +172,9 @@ describe('thumbnail utilities', () => {
     });
     vi.stubGlobal(
       'FileReader',
-      vi.fn(() => mockFileReader),
+      vi.fn(function () {
+        return mockFileReader;
+      }),
     );
 
     createFetchThumbnailTask(

vite.config.ts

@@ -23,23 +23,6 @@ const EXCLUSIONS = [
 ];
 
 const TEST_DIRECTORY = 'tests';
-const INCLUSIONS = [`${TEST_DIRECTORY}/**/*.test.ts`];
-
-// For test performance reasons, tests are split into two groups:
-//
-// - `shared`: run non-isolated, so they share one loaded copy of the source
-//   tree instead of each re-importing it.
-// - `isolated`: given their own module registry per file, because sharing one
-//   would change their behaviour. A file calling `vi.mock()` cannot replace a
-//   module an earlier file already loaded unmocked; a file loading the template
-//   renderer reads browser globals as the renderer loads; and a file needing a
-//   DOM leaves modules holding a `window` that is torn down when it finishes,
-//   which breaks any later file that reaches one of those modules.
-//
-// Absent this variable every test file runs isolated, which is both the safe
-// default and what coverage requires (istanbul only counts a module's top-level
-// code the first time it runs).
-const GROUP = process.env.VITEST_GROUP;
 
 const findTestFiles = (directory: string): string[] => {
   const files: string[] = [];
@@ -54,16 +37,21 @@ const findTestFiles = (directory: string): string[] => {
   return files;
 };
 
-const REQUIRE_ISOLATION_REGEXP =
+// Each test file is read and sorted into one of the projects below, which
-  /\bvi\.(do)?mock\(|loadRenderer|stubConnectedHomeAssistant|@vitest-environment\s+jsdom/;
+// explain what these two properties cost.
+const REQUIRE_ISOLATION_REGEXP = /\bvi\.(do)?mock\(/;
+const REQUIRE_DOM_REGEXP = /@vitest-environment\s+jsdom/;
 
-const getGroup = (file: string): string =>
+const getGroup = (file: string): string => {
-  REQUIRE_ISOLATION_REGEXP.test(readFileSync(file, 'utf-8')) ? 'isolated' : 'shared';
+  const contents = readFileSync(file, 'utf-8');
+  if (REQUIRE_ISOLATION_REGEXP.test(contents)) {
+    return 'isolated';
+  }
+  return REQUIRE_DOM_REGEXP.test(contents) ? 'shared-jsdom' : 'shared-node';
+};
 
-const getInclusions = (): string[] =>
+const getInclusions = (group: string): string[] =>
-  GROUP
+  findTestFiles(TEST_DIRECTORY).filter((file) => getGroup(file) === group);
-    ? findTestFiles(TEST_DIRECTORY).filter((file) => getGroup(file) === GROUP)
-    : INCLUSIONS;
 
 export default defineConfig({
   plugins: [svgPath()],
@@ -75,13 +63,62 @@ export default defineConfig({
         inline: ['ha-nunjucks', 'ts-py-datetime'],
       },
     },
-    include: getInclusions(),
 
     // Forked child processes start and tear down faster here than worker
     // threads, which matters when every test file needs a fresh one.
     pool: 'forks',
 
-    isolate: !GROUP || GROUP === 'isolated',
+    // Importing the source tree costs far more than running the tests in it, so
+    // files are grouped by whether they can share one loaded copy of it. Each
+    // project below is a group that can, or the one that cannot.
+    projects: [
+      {
+        extends: true,
+        test: {
+          // Nothing stops these sharing, so they run against a single loaded
+          // copy of the source tree. Most of the suite is here, and anything
+          // moved out of here pays to import that tree again.
+          name: 'shared-node',
+          include: getInclusions('shared-node'),
+          isolate: false,
+        },
+      },
+      {
+        extends: true,
+        test: {
+          // These share too, but only with each other. A module loaded under
+          // jsdom holds a reference to that DOM, so a worker that moves from a
+          // DOM file to a non-DOM one drops its loaded copy of the source tree
+          // and imports it again. A project's files are spread across workers
+          // without regard to environment, so putting both kinds in one project
+          // leaves every worker alternating between them and reloading as it
+          // goes, and the more workers there are the more often that happens. A
+          // project per environment hands each worker a run of files that all
+          // want the same one. The file-level `@vitest-environment jsdom`
+          // comments are what sort files into here, and are redundant once they
+          // arrive.
+          //
+          // They share one `document` as well, so a file that redefines part of
+          // it must leave the property configurable for the files that follow.
+          name: 'shared-jsdom',
+          include: getInclusions('shared-jsdom'),
+          environment: 'jsdom',
+          isolate: false,
+        },
+      },
+      {
+        extends: true,
+        test: {
+          // `vi.mock()` cannot replace a module that an earlier file already
+          // loaded unmocked, so these cannot share a loaded source tree with
+          // anything, including each other. They get a registry per file and
+          // pay the full import cost.
+          name: 'isolated',
+          include: getInclusions('isolated'),
+          isolate: true,
+        },
+      },
+    ],
 
     // Hide console writing to keep output clean, usual sources of noise:
     // - Unnecessary Lit dev-mode warnings.