Angular 2 Testing RxJS Observable with MockBackend and HTTP

Angular 2 - Testing RxJS Observable with MockBackend and HTTP

import { async, inject, TestBed } from "@angular/core/testing";
import { Http, HttpModule, BaseRequestOptions, RequestMethod, Response, ResponseOptions } from "@angular/http";
import { MockBackend } from "@angular/http/testing";
import { Observable } from "rxjs";

import { MockSessionService } from "../../mocks/session.service.mock";
import { QMSService } from "./qms.service";
import { SessionService } from "../session/session.service";


class SetupTest {
    static mockConnection(mockBackend: MockBackend) {
        let options = new ResponseOptions({
                body: JSON.stringify({ myData: "Something" })
            });

        mockBackend.connections.subscribe((c: any) => c.mockRespond(new Response(options)));
    }
}

describe("QMSService", () => {

    let qmsService: QMSService;
    let sessionService: SessionService;
    let backend: MockBackend;
    let response: any;
    let request: any;

    let HTTP = {
            provide: Http,
            useFactory: (backend: MockBackend, options: BaseRequestOptions) => new Http(backend, options),
            deps: [MockBackend, BaseRequestOptions]
        }

    // Set up mocks for Http backend and mock session service
    beforeEach(() => {
        TestBed.configureTestingModule({
            imports: [HttpModule],
            providers: [
                MockBackend,
                BaseRequestOptions,
                HTTP,
                QMSService,
                { provide: SessionService, useClass: MockSessionService }
            ]
        });
    });

    beforeEach(inject([QMSService, SessionService, MockBackend], (qs: QMSService, ss: SessionService, bkend: MockBackend) => {
        qmsService = qs;
        sessionService = ss;
        backend = bkend;
    }));

    describe("createTraversal", () => {

        it("should get a response", async(() => {

            SetupTest.mockConnection(backend);

            qmsService.createTraversal(123)
                .subscribe((jsr: any) => response = jsr);

            expect(response).toEqual({ myData: "Something" });
        }));
    });

    describe("getCurrentQuestions", () => {

        it("should get a response", async(() => {

            SetupTest.mockConnection(backend);

            qmsService.getCurrentQuestions("/api/current")
                .subscribe((jsr: any) => response = jsr);

            expect(response).toEqual({ myData: "Something" });
        }));
    });

    describe("When answering a question", () => {

        it("should return a response", async(() => {

            SetupTest.mockConnection(backend);

            qmsService.answerQuestion("/some_url", [{"some_key": "SOME_ANSWER"}])
                .subscribe((jsr: any) => response = jsr);

            expect(response).toEqual({ myData: "Something" });
        }));
    });
});