diff --git a/src/app/core/tasks/tasks.service.spec.ts b/src/app/core/tasks/tasks.service.spec.ts
index 1bb4ea46a5..a2ba10f320 100644
--- a/src/app/core/tasks/tasks.service.spec.ts
+++ b/src/app/core/tasks/tasks.service.spec.ts
@@ -21,6 +21,7 @@ import { of as observableOf } from 'rxjs/internal/observable/of';
 import { HttpOptions } from '../dspace-rest/dspace-rest.service';
 import { getMockRemoteDataBuildService } from '../../shared/mocks/remote-data-build.service.mock';
 import { NotificationsServiceStub } from '../../shared/testing/notifications-service.stub';
+import { of } from 'rxjs';
 
 const LINK_NAME = 'test';
 
@@ -124,7 +125,7 @@ describe('TasksService', () => {
     it('should call findByHref with the href generated by getSearchByHref', () => {
 
       spyOn(service, 'getSearchByHref').and.returnValue(observableOf('generatedHref'));
-      spyOn(service, 'findByHref').and.returnValue(null);
+      spyOn(service, 'findByHref').and.returnValue(of(null));
 
       const followLinks = {};
       const options = new FindListOptions();