diff --git a/README.md b/README.md
index c8888c9b..bd5c435c 100644
--- a/README.md
+++ b/README.md
@@ -51,8 +51,7 @@ To install spectator via Yarn run:
   selector: 'app-button',
   template: `
     <button class="{{className}}" (click)="onClick($event)">{{title}}</button>
-  `,
-  styles: []
+  `
 })
 export class ButtonComponent {
   @Input() className = 'success';
@@ -72,7 +71,12 @@ describe('ButtonComponent', () => {
 
   let spectator: Spectator<ButtonComponent>;
   const createComponent = createTestComponentFactory(ButtonComponent);
-
+  
+  // const createComponent = createTestComponentFactory({
+  //   component: ButtonComponent,
+  //   imports: [OtherModule]
+  // });
+  
   it('should set the "success" class by default', () => {
     spectator = createComponent();
     expect(spectator.query('button')).toHaveClass('success');
@@ -92,11 +96,13 @@ describe('ButtonComponent', () => {
   });
 
   it('should emit the $event on click', () => {
-    spectator = createComponent();
+    const detectChanges = false;
+    spectator = createComponent({}, detectChanges);
     let output;
     spectator.output<{ type: string }>('click').subscribe(result => output = result);
 
     spectator.component.onClick({ type: 'click' });
+    spectator.detectChanges();
     expect(output).toEqual({ type: 'click' });
   });
 });
@@ -109,7 +115,7 @@ describe('ButtonComponent', () => {
 @Component({
   selector: 'zippy',
   template: `
-    <div class="zippy" id="zippy">
+    <div class="zippy">
       <div (click)="toggle()" class="zippy__title">
         <span class="arrow">{{ visible ? 'Close' : 'Open' }}</span> {{title}}
       </div>
@@ -297,6 +303,10 @@ describe('TodosService', () => {
   it('should', () => {
     let otherService = spectator.get<OtherService>(OtherService);
     otherService.someMethod.andReturn(customValue);
+    otherService.someMethod.and.callThrough();
+    otherService.someMethod.and.callFake(() => fake);
+    otherService.someMethod.and.throwError('Error');
+    otherService.someMethod.andCallFake(() => fake);
     spectator.service.remove();
     expect(spectator.service.someProp).toBeTruthy();
   });
diff --git a/src/app/todos.service.spec.ts b/src/app/todos.service.spec.ts
index 2b1b0698..c5716b12 100644
--- a/src/app/todos.service.spec.ts
+++ b/src/app/todos.service.spec.ts
@@ -1,6 +1,5 @@
 import { TodosService } from "./todos.service";
 import { createService } from "../lib/src/service";
-import { of } from "rxjs/observable/of";
 
 class OtherService {
   add() {}
@@ -15,7 +14,10 @@ describe("TodosService", () => {
 
   it("should", () => {
     // let otherService = spectator.get<OtherService>(OtherService);
-    // otherService.add.andReturn(of(true));
+    // otherService.add.and.callThrough();
+    // otherService.add.and.callFake(() => fake);
+    // otherService.add.and.throwError('Error');
+    // otherService.add.andCallFake(() => fake);
     spectator.service.remove();
   });
 });
diff --git a/src/lib/src/config.ts b/src/lib/src/config.ts
index 8396b3d6..34b3b3fb 100644
--- a/src/lib/src/config.ts
+++ b/src/lib/src/config.ts
@@ -19,7 +19,7 @@ export type SpectatorOptions<T = any, H = HostComponent> = TestModuleMetadata &
   component?: Type<T>;
   shallow?: boolean;
   disableAnimations?: boolean;
-  host: Type<H>;
+  host?: Type<H>;
 };
 
 const defaultOptions: SpectatorOptions<any, any> = {