diff --git a/packages/service-worker/worker/test/happy_spec.ts b/packages/service-worker/worker/test/happy_spec.ts
index fafff3990b..c1bc37ac1f 100644
--- a/packages/service-worker/worker/test/happy_spec.ts
+++ b/packages/service-worker/worker/test/happy_spec.ts
@@ -12,9 +12,10 @@ import {Driver, DriverReadyState} from '../src/driver';
 import {AssetGroupConfig, DataGroupConfig, Manifest} from '../src/manifest';
 import {sha1} from '../src/sha1';
 import {clearAllCaches, MockCache} from '../testing/cache';
+import {WindowClientImpl} from '../testing/clients';
 import {MockRequest, MockResponse} from '../testing/fetch';
 import {MockFileSystem, MockFileSystemBuilder, MockServerState, MockServerStateBuilder, tmpHashTableForFs} from '../testing/mock';
-import {MockClient, SwTestHarness, SwTestHarnessBuilder, WindowClientImpl} from '../testing/scope';
+import {SwTestHarness, SwTestHarnessBuilder} from '../testing/scope';
 import {envIsSupported} from '../testing/utils';
 
 (function() {
diff --git a/packages/service-worker/worker/testing/clients.ts b/packages/service-worker/worker/testing/clients.ts
new file mode 100644
index 0000000000..a525972ab7
--- /dev/null
+++ b/packages/service-worker/worker/testing/clients.ts
@@ -0,0 +1,77 @@
+/**
+ * @license
+ * Copyright Google LLC All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {Subject} from 'rxjs';
+
+
+export class MockClient {
+  queue = new Subject<Object>();
+
+  constructor(readonly id: string) {}
+
+  readonly messages: Object[] = [];
+
+  postMessage(message: Object): void {
+    this.messages.push(message);
+    this.queue.next(message);
+  }
+}
+
+export class WindowClientImpl extends MockClient implements WindowClient {
+  readonly ancestorOrigins: ReadonlyArray<string> = [];
+  readonly focused: boolean = false;
+  readonly visibilityState: VisibilityState = 'hidden';
+  frameType: ClientFrameType = 'top-level';
+  url = 'http://localhost/unique';
+
+  constructor(readonly id: string) {
+    super(id);
+  }
+
+  async focus(): Promise<WindowClient> {
+    return this;
+  }
+
+  async navigate(url: string): Promise<WindowClient|null> {
+    return this;
+  }
+}
+
+export class MockClients implements Clients {
+  private clients = new Map<string, MockClient>();
+
+  add(clientId: string): void {
+    if (this.clients.has(clientId)) {
+      return;
+    }
+    this.clients.set(clientId, new MockClient(clientId));
+  }
+
+  remove(clientId: string): void {
+    this.clients.delete(clientId);
+  }
+
+  async get(id: string): Promise<Client> {
+    return this.clients.get(id)! as any as Client;
+  }
+
+  getMock(id: string): MockClient|undefined {
+    return this.clients.get(id);
+  }
+
+  async matchAll<T extends ClientQueryOptions>(options?: T):
+      Promise<ReadonlyArray<T['type'] extends 'window'? WindowClient : Client>> {
+    return Array.from(this.clients.values()) as any[];
+  }
+
+  async openWindow(url: string): Promise<WindowClient|null> {
+    return null;
+  }
+
+  async claim(): Promise<any> {}
+}
diff --git a/packages/service-worker/worker/testing/scope.ts b/packages/service-worker/worker/testing/scope.ts
index 3dd0dcac5b..ddf6dd9a31 100644
--- a/packages/service-worker/worker/testing/scope.ts
+++ b/packages/service-worker/worker/testing/scope.ts
@@ -6,13 +6,12 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Subject} from 'rxjs';
-
 import {Adapter} from '../src/adapter';
 import {AssetGroupConfig, Manifest} from '../src/manifest';
 import {sha1} from '../src/sha1';
 
 import {MockCacheStorage} from './cache';
+import {MockClient, MockClients} from './clients';
 import {MockActivateEvent, MockExtendableMessageEvent, MockFetchEvent, MockInstallEvent, MockNotificationEvent, MockPushEvent} from './events';
 import {MockHeaders, MockRequest, MockResponse} from './fetch';
 import {MockServerState, MockServerStateBuilder} from './mock';
@@ -20,37 +19,6 @@ import {normalizeUrl, parseUrl} from './utils';
 
 const EMPTY_SERVER_STATE = new MockServerStateBuilder().build();
 
-export class MockClient {
-  queue = new Subject<Object>();
-
-  constructor(readonly id: string) {}
-
-  readonly messages: Object[] = [];
-
-  postMessage(message: Object): void {
-    this.messages.push(message);
-    this.queue.next(message);
-  }
-}
-export class WindowClientImpl extends MockClient implements WindowClient {
-  readonly ancestorOrigins: ReadonlyArray<string> = [];
-  readonly focused: boolean = false;
-  readonly visibilityState: VisibilityState = 'hidden';
-  frameType: ClientFrameType = 'top-level';
-  url = 'http://localhost/unique';
-
-  constructor(readonly id: string) {
-    super(id);
-  }
-
-  async focus(): Promise<WindowClient> {
-    return this;
-  }
-  async navigate(url: string): Promise<WindowClient|null> {
-    return this;
-  }
-}
-
 export class SwTestHarnessBuilder {
   private origin = parseUrl(this.scopeUrl).origin;
   private server = EMPTY_SERVER_STATE;
@@ -73,39 +41,6 @@ export class SwTestHarnessBuilder {
   }
 }
 
-export class MockClients implements Clients {
-  private clients = new Map<string, MockClient>();
-
-  add(clientId: string): void {
-    if (this.clients.has(clientId)) {
-      return;
-    }
-    this.clients.set(clientId, new MockClient(clientId));
-  }
-
-  remove(clientId: string): void {
-    this.clients.delete(clientId);
-  }
-
-  async get(id: string): Promise<Client> {
-    return this.clients.get(id)! as any as Client;
-  }
-
-  getMock(id: string): MockClient|undefined {
-    return this.clients.get(id);
-  }
-
-  async matchAll<T extends ClientQueryOptions>(options?: T):
-      Promise<ReadonlyArray<T['type'] extends 'window'? WindowClient : Client>> {
-    return Array.from(this.clients.values()) as any[];
-  }
-  async openWindow(url: string): Promise<WindowClient|null> {
-    return null;
-  }
-
-  async claim(): Promise<any> {}
-}
-
 export class SwTestHarness extends Adapter<MockCacheStorage> implements ServiceWorkerGlobalScope {
   readonly clients = new MockClients();
   private eventHandlers = new Map<string, Function>();