Angular Testing Course

Author: jhades

src/app/app.component.spec.ts

@@ -6,6 +6,8 @@ import {NoopAnimationsModule} from '@angular/platform-browser/animations';
 import {By} from '@angular/platform-browser';
 
 describe('AppComponent', () => {
+
+
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       imports: [
@@ -22,22 +24,34 @@ describe('AppComponent', () => {
     }).compileComponents();
   }));
 
+
+
   it('should create the app', async(() => {
+
     const fixture = TestBed.createComponent(AppComponent);
     const app = fixture.debugElement.componentInstance;
     expect(app).toBeTruthy();
+
   }));
 
-  it(`should have as title 'app'`, async(() => {
+
+
+  it(`should have a title property`, async(() => {
+
     const fixture = TestBed.createComponent(AppComponent);
     const app = fixture.debugElement.componentInstance;
     expect(app.title).toEqual('Angular Testing Course');
+
   }));
 
-  it('should render home component title', async(() => {
+
+
+  it('should have a navigation menu', async(() => {
+
     const fixture = TestBed.createComponent(AppComponent);
     fixture.detectChanges();
     expect(fixture.debugElement.queryAll(By.css('mat-toolbar'))).toBeTruthy();
+
   }));
 
 });

src/app/services/calculator.service.spec.ts

@@ -0,0 +1,49 @@
+import {CalculatorService} from './calculator.service';
+import {LoggerService} from './logger.service';
+
+
+describe('CalculatorService', () => {
+
+  let calculator: CalculatorService,
+      loggerSpy:any;
+
+  beforeEach(() => {
+
+    console.log("Calling beforeEach()");
+
+    loggerSpy = jasmine.createSpyObj('LoggerService', ['log']);
+
+    loggerSpy.log.and.returnValue(undefined);
+
+    calculator = new CalculatorService(loggerSpy);
+
+  });
+
+  it("should add two numbers", () => {
+
+    const result = calculator.add(2, 2);
+
+    expect(result).toBe(4);
+
+    expect(loggerSpy.log.calls.count())
+      .toBe(1, 'logger method should only be called once');
+
+    expect(loggerSpy.log).toHaveBeenCalledWith("Addition operation called");
+
+  });
+
+
+  it("should subtract two numbers", () => {
+
+    const result = calculator.subtract(2, 2);
+
+    expect(result).toBe(0);
+
+    expect(loggerSpy.log.calls.count())
+      .toBe(1, 'logger method should only be called once');
+
+    expect(loggerSpy.log).toHaveBeenCalledWith("Subtraction operation called");
+
+  });
+
+});

src/app/services/calculator.service.ts

@@ -0,0 +1,27 @@
+import {Injectable} from '@angular/core';
+import {LoggerService} from './logger.service';
+
+
+@Injectable({
+  providedIn: 'root'
+})
+export class CalculatorService {
+
+
+  constructor(private logger: LoggerService) {
+
+  }
+
+  add(n1: number, n2:number) {
+    this.logger.log("Addition operation called");
+    return n1 + n2;
+  }
+
+  subtract(n1: number, n2:number) {
+    this.logger.log("Subtraction operation called");
+    return n1 - n2;
+  }
+
+
+}
+

src/app/services/logger.service.ts

@@ -0,0 +1,13 @@
+import {Injectable} from '@angular/core';
+
+
+@Injectable({
+  providedIn: 'root'
+})
+export class LoggerService {
+
+  log(message:string) {
+    console.log(message);
+  }
+
+}