Testing Angular components

We have just seen how to test a service in Angular application. Now, let's discuss testing an Angular component. Perform the following steps to create AppComponent for the application:

1. Create a file named app.component.ts.

2. Import modules such as Component, TodoService, and Todo that are necessary for the AppComponent, as shown:

        import { Component } from '@angular/core'; 
        import { Todo } from './todo'; 
        import { TodoService } from './todo.service'; 

3. Define the AppComponent class, as demonstrated:

        export class AppComponent {} 

4. Decorate the AppComponent class by the @Component attribute with the selector, providers and templateUrl metadata:

        @Component({ 
            selector: 'my-app', 
            templateUrl: './app.component.html', 
            providers: [TodoService] 
        }) 
        export class AppComponent {     
        } 

5. Declare the todos, todoService, newTodoText, and title variables:

        todos: Array<Todo>...