Courses service unit test

Author: tpersaud27

src/app/courses/services/courses.services.spec.ts

@@ -0,0 +1,46 @@
+import { TestBed } from "@angular/core/testing";
+import { CoursesService } from "./courses.service";
+import {
+  HttpClientTestingModule,
+  HttpTestingController,
+} from "@angular/common/http/testing";
+import { COURSES } from "../../../../server/db-data";
+
+describe("CoursesService", () => {
+  let coursesService: CoursesService;
+  let httpTestingController: HttpTestingController;
+
+  beforeEach(() => {
+    // TestBed creates a angular module that will contain the instance of our service
+    TestBed.configureTestingModule({
+      // HttpClientTestingModule has a mock implementation of the http service
+      // This mock implementation will have all the same actions at the http service
+      imports: [HttpClientTestingModule],
+      providers: [CoursesService],
+    });
+    coursesService = TestBed.inject(CoursesService);
+    httpTestingController = TestBed.inject(HttpTestingController);
+  });
+
+  it("should retrieve all courses", () => {
+    coursesService.findAllCourses().subscribe({
+      next: (courses) => {
+        // First we expect to get some data back
+        expect(courses).toBeTruthy("No courses returned");
+        // Check the number of courses
+        expect(courses.length).toBe(12, "Incorrect number of courses");
+        // Check if this course instance exists
+        const course = courses.find((course) => course.id == 12);
+        expect(course.titles.description).toBe("Angular Testing Course");
+      },
+    });
+    // We expect one request to be sent at this endpoint
+    const request = httpTestingController.expectOne("/api/courses");
+    // We expect the request to be a GET request
+    expect(request.request.method).toEqual("GET");
+
+    // We should specify which data should be returned
+    // This is some test data
+    request.flush({ payload: Object.values(COURSES) });
+  });
+});