diff --git a/packages/service-worker/src/low_level.ts b/packages/service-worker/src/low_level.ts
index 48a6c45316..1632ca6bbd 100644
--- a/packages/service-worker/src/low_level.ts
+++ b/packages/service-worker/src/low_level.ts
@@ -106,8 +106,7 @@ export class NgswCommChannel {
       this.registration = <Observable<ServiceWorkerRegistration>>(
           op_switchMap.call(this.worker, () => serviceWorker.getRegistration()));
 
-      const rawEvents = <Observable<MessageEvent>>(op_switchMap.call(
-          this.registration, (reg: ServiceWorkerRegistration) => obs_fromEvent(reg, 'message')));
+      const rawEvents = obs_fromEvent(serviceWorker, 'message');
 
       const rawEventPayload =
           <Observable<Object>>(op_map.call(rawEvents, (event: MessageEvent) => event.data));
diff --git a/packages/service-worker/test/comm_spec.ts b/packages/service-worker/test/comm_spec.ts
index 299af592c6..c1c0d75c80 100644
--- a/packages/service-worker/test/comm_spec.ts
+++ b/packages/service-worker/test/comm_spec.ts
@@ -44,11 +44,9 @@ export function main() {
     });
     describe('SwPush', () => {
       let push: SwPush;
-      let reg: MockServiceWorkerRegistration;
-      beforeEach((done: DoneFn) => {
+      beforeEach(() => {
         push = new SwPush(comm);
         mock.setupSw();
-        mock.mockRegistration.then(r => reg = r).then(() => done());
       });
       it('receives push messages', (done: DoneFn) => {
         push.messages.subscribe(msg => {
@@ -57,7 +55,7 @@ export function main() {
           });
           done();
         });
-        reg.sendMessage({
+        mock.sendMessage({
           type: 'PUSH',
           data: {
             message: 'this was a push message',
@@ -76,11 +74,9 @@ export function main() {
     });
     describe('SwUpdate', () => {
       let update: SwUpdate;
-      let reg: MockServiceWorkerRegistration;
-      beforeEach((done: DoneFn) => {
+      beforeEach(() => {
         update = new SwUpdate(comm);
         mock.setupSw();
-        mock.mockRegistration.then(r => reg = r).then(() => done());
       });
       it('processes update availability notifications when sent', (done: DoneFn) => {
         update.available.subscribe(event => {
@@ -89,7 +85,7 @@ export function main() {
           expect(event.type).toEqual('UPDATE_AVAILABLE');
           done();
         });
-        reg.sendMessage({
+        mock.sendMessage({
           type: 'UPDATE_AVAILABLE',
           current: {
             version: 'A',
@@ -106,7 +102,7 @@ export function main() {
           expect(event.type).toEqual('UPDATE_ACTIVATED');
           done();
         });
-        reg.sendMessage({
+        mock.sendMessage({
           type: 'UPDATE_ACTIVATED',
           previous: {
             version: 'A',
@@ -119,7 +115,7 @@ export function main() {
       it('activates updates when requested', (done: DoneFn) => {
         mock.messages.subscribe((msg: {action: string, statusNonce: number}) => {
           expect(msg.action).toEqual('ACTIVATE_UPDATE');
-          reg.sendMessage({
+          mock.sendMessage({
             type: 'STATUS',
             nonce: msg.statusNonce,
             status: true,
@@ -130,7 +126,7 @@ export function main() {
       it('reports activation failure when requested', (done: DoneFn) => {
         mock.messages.subscribe((msg: {action: string, statusNonce: number}) => {
           expect(msg.action).toEqual('ACTIVATE_UPDATE');
-          reg.sendMessage({
+          mock.sendMessage({
             type: 'STATUS',
             nonce: msg.statusNonce,
             status: false,
diff --git a/packages/service-worker/test/integration_spec.ts b/packages/service-worker/test/integration_spec.ts
index 1b3686a32b..de069c3534 100644
--- a/packages/service-worker/test/integration_spec.ts
+++ b/packages/service-worker/test/integration_spec.ts
@@ -85,7 +85,7 @@ export function main() {
       driver = new Driver(scope, scope, new CacheDatabase(scope, scope));
 
       scope.clients.add('default');
-      scope.clients.getMock('default') !.queue.subscribe(msg => { reg.sendMessage(msg); });
+      scope.clients.getMock('default') !.queue.subscribe(msg => { mock.sendMessage(msg); });
 
       mock.messages.subscribe(msg => { scope.handleMessage(msg, 'default'); });
 
diff --git a/packages/service-worker/testing/mock.ts b/packages/service-worker/testing/mock.ts
index 42dccc2da4..0d28454990 100644
--- a/packages/service-worker/testing/mock.ts
+++ b/packages/service-worker/testing/mock.ts
@@ -10,17 +10,26 @@ import {Subject} from 'rxjs/Subject';
 
 export class MockServiceWorkerContainer {
   private onControllerChange: Function[] = [];
+  private onMessage: Function[] = [];
   private registration: MockServiceWorkerRegistration|null = null;
   controller: MockServiceWorker|null = null;
 
   messages = new Subject();
 
-  addEventListener(event: 'controllerchange', handler: Function) {
-    this.onControllerChange.push(handler);
+  addEventListener(event: 'controllerchange'|'message', handler: Function) {
+    if (event === 'controllerchange') {
+      this.onControllerChange.push(handler);
+    } else if (event === 'message') {
+      this.onMessage.push(handler);
+    }
   }
 
   removeEventListener(event: 'controllerchange', handler: Function) {
-    this.onControllerChange = this.onControllerChange.filter(h => h !== handler);
+    if (event === 'controllerchange') {
+      this.onControllerChange = this.onControllerChange.filter(h => h !== handler);
+    } else if (event === 'message') {
+      this.onMessage = this.onMessage.filter(h => h !== handler);
+    }
   }
 
   async register(url: string): Promise<void> { return; }
@@ -36,6 +45,12 @@ export class MockServiceWorkerContainer {
   get mockRegistration(): Promise<MockServiceWorkerRegistration> {
     return Promise.resolve(this.registration !);
   }
+
+  sendMessage(value: Object): void {
+    this.onMessage.forEach(onMessage => onMessage({
+                             data: value,
+                           }));
+  }
 }
 
 export class MockServiceWorker {
@@ -44,21 +59,4 @@ export class MockServiceWorker {
   postMessage(value: Object) { this.mock.messages.next(value); }
 }
 
-export class MockServiceWorkerRegistration {
-  private onMessage: Function[] = [];
-  messages: Object[] = [];
-
-  constructor() {}
-
-  addEventListener(event: 'message', handler: Function) { this.onMessage.push(handler); }
-
-  removeEventListener(event: 'message', handler: Function) {
-    this.onMessage = this.onMessage.filter(h => h !== handler);
-  }
-
-  sendMessage(value: Object): void {
-    this.onMessage.forEach(onMessage => onMessage({
-                             data: value,
-                           }));
-  }
-}
\ No newline at end of file
+export class MockServiceWorkerRegistration {}