added tests for collections component

src/app/+item-page/field-components/collections/collections.component.spec.ts

+import { CollectionsComponent } from './collections.component';
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+import { ChangeDetectionStrategy, NO_ERRORS_SCHEMA } from '@angular/core';
+import { By } from '@angular/platform-browser';
+import { Collection } from '../../../core/shared/collection.model';
+import { RemoteDataBuildService } from '../../../core/cache/builders/remote-data-build.service';
+import { getMockRemoteDataBuildService } from '../../../shared/mocks/mock-remote-data-build.service';
+import { Item } from '../../../core/shared/item.model';
+import { Observable } from 'rxjs/Observable';
+import { RemoteData } from '../../../core/data/remote-data';
+import { TranslateModule } from '@ngx-translate/core';
+
+let collectionsComponent: CollectionsComponent;
+let fixture: ComponentFixture<CollectionsComponent>;
+
+const mockCollection1: Collection = Object.assign(new Collection(), {
+  metadata: [
+    {
+      key: 'dc.description.abstract',
+      language: 'en_US',
+      value: 'Short description'
+    }]
+});
+
+const succeededMockItem: Item = Object.assign(new Item(), {owningCollection: Observable.of(new RemoteData(false, false, true, null, mockCollection1))});
+const failedMockItem: Item = Object.assign(new Item(), {owningCollection: Observable.of(new RemoteData(false, false, false, null, mockCollection1))});
+
+describe('CollectionsComponent', () => {
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      imports: [TranslateModule.forRoot()],
+      declarations: [ CollectionsComponent ],
+      providers: [
+        { provide: RemoteDataBuildService, useValue: getMockRemoteDataBuildService()}
+      ],
+
+      schemas: [ NO_ERRORS_SCHEMA ]
+    }).overrideComponent(CollectionsComponent, {
+      set: { changeDetection: ChangeDetectionStrategy.Default }
+    }).compileComponents();
+  }));
+
+  beforeEach(async(() => {
+    fixture = TestBed.createComponent(CollectionsComponent);
+    collectionsComponent = fixture.componentInstance;
+    collectionsComponent.label = 'test.test';
+    collectionsComponent.separator = '<br/>';
+
+  }));
+
+  describe('When the requested item request has succeeded', () => {
+    beforeEach(() => {
+      collectionsComponent.item = succeededMockItem;
+      fixture.detectChanges();
+    });
+
+    it('should show the collection', () => {
+      const collectionField = fixture.debugElement.query(By.css('ds-metadata-field-wrapper div.collections'));
+      expect(collectionField).not.toBeNull();
+    });
+  });
+
+  describe('When the requested item request has succeeded', () => {
+    beforeEach(() => {
+      collectionsComponent.item = failedMockItem;
+      fixture.detectChanges();
+    });
+
+    it('should not show the collection', () => {
+      const collectionField = fixture.debugElement.query(By.css('ds-metadata-field-wrapper div.collections'));
+      expect(collectionField).toBeNull();
+    });
+  });
+});