diff --git a/frontend/package.json b/frontend/package.json
index 164243531..d25828e83 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -31,7 +31,7 @@
     "font-awesome": "4.7.0",
     "luxon": "1.0.0",
     "rxjs": "5.5.8",
-    "zone.js": "0.8.20"
+    "zone.js": "0.8.25"
   },
   "devDependencies": {
     "@angular/cli": "1.7.3",
diff --git a/frontend/src/app/cities-upload/cities-upload.component.spec.ts b/frontend/src/app/cities-upload/cities-upload.component.spec.ts
index 9981b6cd1..8d59aa09e 100644
--- a/frontend/src/app/cities-upload/cities-upload.component.spec.ts
+++ b/frontend/src/app/cities-upload/cities-upload.component.spec.ts
@@ -1,170 +1,159 @@
-import { async, fakeAsync, TestBed, tick } from '@angular/core/testing';
+import { TestBed } from '@angular/core/testing';
 
 import { CitiesUploadComponent } from './cities-upload.component';
 import { SearchCityService } from '../search-city.service';
 import { Subject } from 'rxjs/Subject';
 import { HttpClientModule, HttpEventType, HttpResponse } from '@angular/common/http';
-import { DateTime } from 'luxon';
 import { GlobeNgbModule } from '../globe-ngb/globe-ngb.module';
 
-class FakeNow {
-  private now = DateTime.local();
+// TODO: those three lines of code can be removed after new version of angular is released.
+declare let Zone: any;
+const { fakeAsync, tick } = Zone['__zone_symbol__fakeAsyncTest'];
+const async = Zone['__zone_symbol__asyncTest'];
 
-  constructor() {
-    jasmine.clock().mockDate(this.now.toJSDate());
-  }
-
-  tickSeconds(seconds: number) {
-    this.now = this.now.plus({ seconds });
-    jasmine.clock().mockDate(this.now.toJSDate());
-    tick(seconds * 1000);
-  }
+function tickSeconds(seconds: number) {
+  tick(seconds * 1000);
 }
 
 describe('CitiesUploadComponent', () => {
-
-  beforeEach(async(() => {
-    TestBed.configureTestingModule({
-      imports: [GlobeNgbModule.forRoot(), HttpClientModule],
-      declarations: [CitiesUploadComponent],
-      providers: [SearchCityService]
-    });
-  }));
-
-  afterEach(() => jasmine.clock().uninstall());
+  beforeEach(
+    async(() => {
+      TestBed.configureTestingModule({
+        imports: [GlobeNgbModule.forRoot(), HttpClientModule],
+        declarations: [CitiesUploadComponent],
+        providers: [SearchCityService]
+      });
+    })
+  );
 
   it('should upload', fakeAsync(() => {
-    const cityService = TestBed.get(SearchCityService);
-    const component = new CitiesUploadComponent(cityService);
-
-    expect(component.status).toBe('pending');
+      const cityService = TestBed.get(SearchCityService);
+      const component = new CitiesUploadComponent(cityService);
 
-    const fileChangeEvent = {
-      target: {
-        files: ['fakeFile']
-      }
-    } as any;
+      expect(component.status).toBe('pending');
 
-    const fileReader = new FileReader();
-    spyOn(fileReader, 'readAsText');
+      const fileChangeEvent = {
+        target: {
+          files: ['fakeFile']
+        }
+      } as any;
 
-    spyOn(component, '_createFileReader').and.returnValue(fileReader);
+      const fileReader = new FileReader();
+      spyOn(fileReader, 'readAsText');
 
-    const fakeNow = new FakeNow();
+      spyOn(component, '_createFileReader').and.returnValue(fileReader);
 
-    component.upload(fileChangeEvent);
-    expect(fileReader.onload).toBeDefined();
-    expect(fileReader.readAsText).toHaveBeenCalledWith('fakeFile', 'UTF8');
+      component.upload(fileChangeEvent);
+      expect(fileReader.onload).toBeDefined();
+      expect(fileReader.readAsText).toHaveBeenCalledWith('fakeFile', 'UTF8');
 
-    const fileLoadedEvent: any = {
-      target: {
-        result: 'fakeFileContent'
-      }
-    };
+      const fileLoadedEvent: any = {
+        target: {
+          result: 'fakeFileContent'
+        }
+      };
 
-    const fakeEvents = new Subject<any>();
-    spyOn(cityService, 'uploadCities').and.returnValue(fakeEvents);
+      const fakeEvents = new Subject<any>();
+      spyOn(cityService, 'uploadCities').and.returnValue(fakeEvents);
 
-    fileReader.onload(fileLoadedEvent);
-    expect(component.status).toBe('uploading');
+      fileReader.onload(fileLoadedEvent);
+      expect(component.status).toBe('uploading');
 
-    // emit first progress event after 5 seconds
-    fakeNow.tickSeconds(5);
-    fakeEvents.next({
-      type: HttpEventType.UploadProgress,
-      loaded: 5,
-      total: 10
-    });
+      tickSeconds(5);
+      fakeEvents.next({
+        type: HttpEventType.UploadProgress,
+        loaded: 5,
+        total: 10
+      });
 
-    // upload is halfway and has taken 5 seconds. Estimated processing time is 20 seconds
-    // so total time is 30 seconds and we're thus at 5 / 30
-    expect(component.progress).toBe(5 / 30);
+      // upload is halfway and has taken 5 seconds. Estimated processing time is 20 seconds
+      // so total time is 30 seconds and we're thus at 5 / 30
+      expect(component.progress).toBe(5 / 30);
 
-    // emit last progress events
-    fakeNow.tickSeconds(5);
-    fakeEvents.next({
-      type: HttpEventType.UploadProgress,
-      loaded: 10,
-      total: 10
-    });
+      tickSeconds(5);
+      fakeEvents.next({
+        type: HttpEventType.UploadProgress,
+        loaded: 10,
+        total: 10
+      });
 
-    expect(component.progress).toBe(10 / 30);
-    expect(component.status).toBe('processing');
+      expect(component.progress).toBe(10 / 30);
+      expect(component.status).toBe('processing');
 
-    fakeNow.tickSeconds(10);
-    expect(component.progress).toBe(20 / 30);
+      tickSeconds(10);
+      expect(component.progress).toBe(20 / 30);
 
-    fakeNow.tickSeconds(5);
-    expect(component.progress).toBe(25 / 30);
+      tickSeconds(5);
+      expect(component.progress).toBe(25 / 30);
 
-    fakeNow.tickSeconds(6);
-    expect(component.progress).toBeLessThan(1);
-    expect(component.status).toBe('processing');
+      tickSeconds(6);
+      expect(component.progress).toBeLessThan(1);
+      expect(component.status).toBe('processing');
 
-    // emit response and complete
-    fakeEvents.next(new HttpResponse());
-    fakeEvents.complete();
-    expect(component.progress).toBe(1);
-    expect(component.status).toBe('done');
-  }));
+      // emit response and complete
+      fakeEvents.next(new HttpResponse());
+      fakeEvents.complete();
+      expect(component.progress).toBe(1);
+      expect(component.status).toBe('done');
+    })
+  );
 
   it('should finish if response comes back early', fakeAsync(() => {
-    const cityService = TestBed.get(SearchCityService);
-    const component = new CitiesUploadComponent(cityService);
-
-    expect(component.status).toBe('pending');
-
-    const fileChangeEvent = {
-      target: {
-        files: ['fakeFile']
-      }
-    } as any;
-
-    const fileReader = new FileReader();
-    spyOn(fileReader, 'readAsText');
-    spyOn(component, '_createFileReader').and.returnValue(fileReader);
-
-    const fakeNow = new FakeNow();
-
-    component.upload(fileChangeEvent);
-    expect(fileReader.onload).toBeDefined();
-    expect(fileReader.readAsText).toHaveBeenCalledWith('fakeFile', 'UTF8');
-
-    const fileLoadedEvent: any = {
-      target: {
-        result: 'fakeFileContent'
-      }
-    };
-
-    const fakeEvents = new Subject<any>();
-    spyOn(cityService, 'uploadCities').and.returnValue(fakeEvents);
-
-    fileReader.onload(fileLoadedEvent);
-    expect(component.status).toBe('uploading');
-
-    // emit last progress events
-    fakeNow.tickSeconds(10);
-    fakeEvents.next({
-      type: HttpEventType.UploadProgress,
-      loaded: 10,
-      total: 10
-    });
-
-    expect(component.progress).toBe(10 / 30);
-    expect(component.status).toBe('processing');
-
-    fakeNow.tickSeconds(15);
-    expect(component.progress).toBe(25 / 30);
-
-    // emit response and complete
-    fakeEvents.next(new HttpResponse());
-    fakeEvents.complete();
-    expect(component.progress).toBe(1);
-    expect(component.status).toBe('done');
-
-    // let the fake event observable a chance to realize that the processing is done
-    fakeNow.tickSeconds(1);
-  }));
+      const cityService = TestBed.get(SearchCityService);
+      const component = new CitiesUploadComponent(cityService);
+
+      expect(component.status).toBe('pending');
+
+      const fileChangeEvent = {
+        target: {
+          files: ['fakeFile']
+        }
+      } as any;
+
+      const fileReader = new FileReader();
+      spyOn(fileReader, 'readAsText');
+      spyOn(component, '_createFileReader').and.returnValue(fileReader);
+
+      component.upload(fileChangeEvent);
+      expect(fileReader.onload).toBeDefined();
+      expect(fileReader.readAsText).toHaveBeenCalledWith('fakeFile', 'UTF8');
+
+      const fileLoadedEvent: any = {
+        target: {
+          result: 'fakeFileContent'
+        }
+      };
+
+      const fakeEvents = new Subject<any>();
+      spyOn(cityService, 'uploadCities').and.returnValue(fakeEvents);
+
+      fileReader.onload(fileLoadedEvent);
+      expect(component.status).toBe('uploading');
+
+      // emit last progress events
+      tickSeconds(10);
+      fakeEvents.next({
+        type: HttpEventType.UploadProgress,
+        loaded: 10,
+        total: 10
+      });
+
+      expect(component.progress).toBe(10 / 30);
+      expect(component.status).toBe('processing');
+
+      tickSeconds(15);
+      expect(component.progress).toBe(25 / 30);
+
+      // emit response and complete
+      fakeEvents.next(new HttpResponse());
+      fakeEvents.complete();
+      expect(component.progress).toBe(1);
+      expect(component.status).toBe('done');
+
+      // let the fake event observable a chance to realize that the processing is done
+      tickSeconds(1);
+    })
+  );
 
   it('should display an info message and a file upload control, and no progress', () => {
     const fixture = TestBed.createComponent(CitiesUploadComponent);
diff --git a/frontend/yarn.lock b/frontend/yarn.lock
index 322210248..7a4b59c26 100644
--- a/frontend/yarn.lock
+++ b/frontend/yarn.lock
@@ -7341,6 +7341,6 @@ yn@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/yn/-/yn-2.0.0.tgz#e5adabc8acf408f6385fc76495684c88e6af689a"
 
-zone.js@0.8.20:
-  version "0.8.20"
-  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.8.20.tgz#a218c48db09464b19ff6fc8f0d4bb5b1046e185d"
+zone.js@0.8.25:
+  version "0.8.25"
+  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.8.25.tgz#e20e5e85b881e2e66352612b5f238e8309e5badd"