fix: Fixed app update test

src/app/services/app-update.service.spec.ts

@@ -1,16 +1,68 @@
-import { TestBed } from '@angular/core/testing'
+import { ComponentFixture, TestBed } from '@angular/core/testing'
 
 import { AppUpdateService } from './app-update.service'
+import { SwUpdate } from '@angular/service-worker'
+import { of } from 'rxjs'
+import { MATERIAL_ANIMATIONS } from '@angular/material/core'
+import { HarnessLoader } from '@angular/cdk/testing'
+import { TestbedHarnessEnvironment } from '@angular/cdk/testing/testbed'
+import { MatSnackBarHarness } from "@angular/material/snack-bar/testing";
+import { Component } from '@angular/core'
+
+@Component({
+  standalone: false,
+})
+class BlankPage {
+  constructor (private au: AppUpdateService) {}
+}
 
 describe('AppUpdateService', () => {
+  let fixture: ComponentFixture<BlankPage>
+  let loader: HarnessLoader
   let service: AppUpdateService
+  let swuMock: jasmine.SpyObj<SwUpdate>
 
   beforeEach(() => {
-    TestBed.configureTestingModule({})
+    swuMock = jasmine.createSpyObj("SwUpdate", {
+      checkForUpdate: new Promise(() => {}),
+    }, {
+      versionUpdates: of()
+    })
+    TestBed.configureTestingModule({
+      declarations: [BlankPage],
+      providers: [
+        {provide: SwUpdate, useValue: swuMock},
+        {provide: MATERIAL_ANIMATIONS, useValue: { animationsDisabled: true }}
+      ]
+    })
+    fixture = TestBed.createComponent(BlankPage)
+    fixture.detectChanges()
     service = TestBed.inject(AppUpdateService)
+    loader = TestbedHarnessEnvironment.documentRootLoader(fixture)
+
   })
 
-  xit('should be created', () => {
+  it('should be created', () => {
     expect(service).toBeTruthy()
   })
+
+  it('should load harness for snackbar', async () => {
+    service.promptUser()
+    let snackBars = await loader.getAllHarnesses(MatSnackBarHarness);
+
+    expect(snackBars.length).toBe(1)
+  })
+
+  it('should be able to get snackbar content', async () => {
+    service.promptUser()
+    let snackBar = await loader.getHarness(MatSnackBarHarness)
+    expect(await snackBar.getMessage()).toBeDefined()
+  })
+
+  it('should be able to get snackbar action', async () => {
+    service.promptUser()
+    let snackBar = await loader.getHarness(MatSnackBarHarness)
+    expect(await snackBar.getActionDescription()).toBeDefined()
+  })
+
 })