fixed an issue where certain GET requests would be performed more often then needed and added tests for the requestservice (not everything tested yet)

src/app/shared/mocks/mock-object-cache.service.ts

@@ -0,0 +1,7 @@
+import { ObjectCacheService } from '../../core/cache/object-cache.service';
+
+export function initMockObjectCacheService(): ObjectCacheService {
+  return jasmine.createSpyObj('objectCacheService', {
+    hasBySelfLink: true,
+  });
+}