Migrate Testing from Karma to Jest

[rrchai]

# run unit test
npm test
# run unit test with coverage
npm run test:coverage
# run e2e test
npm run test:e2e

Resources:

• jest-preset-angular
• Jest Config
• Jest CLI

[rrchai]

errors raised from jest testing and how to solve it:

1. add import { BrowserAnimationsModule } from '@angular/platform-browser/animations';

   Unexpected synthetic property @transitionMessages found. Please make sure that:
     - Either `BrowserAnimationsModule` or `NoopAnimationsModule` are imported in your application.
     - There is corresponding configuration for the animation named `@transitionMessages` defined in the `animations` field of the `@Component` decorator (see https://angular.io/api/core/Component#animations).

2. add import { RouterTestingModule } from '@angular/router/testing';

   NullInjectorError: R3InjectorError(DynamicTestModule)[Router -> Router]: 
     NullInjectorError: No provider for Router!

3. add import { HttpClientModule } from '@angular/common/http';

   NullInjectorError: R3InjectorError(DynamicTestModule)[AuthService -> AuthService -> HttpClient -> HttpHandler -> HttpHandler]: 
     NullInjectorError: No provider for HttpHandler!

4. It means you are missing corresponding module and you would need to import the module in the *.spec.ts file

   'xxx' is an Angular component, then verify that it is part of this module
   or 
   Export of name 'xxx' not found!