added error component and coverage for new components

src/app/shared/loading/loading.component.spec.ts

@@ -0,0 +1,45 @@
+import { ComponentFixture, TestBed, async } from '@angular/core/testing';
+import { By } from '@angular/platform-browser';
+import { DebugElement } from '@angular/core';
+
+import { LoadingComponent } from './loading.component';
+
+describe('LoadingComponent (inline template)', () => {
+
+  let comp: LoadingComponent;
+  let fixture: ComponentFixture<LoadingComponent>;
+  let de: DebugElement;
+  let el: HTMLElement;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [ LoadingComponent ], // declare the test component
+    }).compileComponents();  // compile template and css
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(LoadingComponent);
+
+    comp = fixture.componentInstance; // LoadingComponent test instance
+
+    // query for the title <div> by CSS element selector
+    de = fixture.debugElement.query(By.css('div'));
+    el = de.nativeElement;
+  });
+
+  it('should create', () => {
+    expect(comp).toBeTruthy();
+  });
+
+  it('should display default message', () => {
+    fixture.detectChanges();
+    expect(el.textContent).toContain(comp.message);
+  });
+
+  it('should display input message', () => {
+    comp.message = 'Test Message';
+    fixture.detectChanges();
+    expect(el.textContent).toContain('Test Message');
+  });
+
+});