Unit Test Breeze calls for Aurelia - jasmine

Question

I have converted my fetch calls to use breeze.EntityQuery but how can I write my unit tests to mock the breeze client? Here is my code for the unit test fetch call that I'm trying to write for breeze.
class HttpStub {
fetch(url) {
var response = this.itemStub;
this.url = url;
return new Promise((resolve) => {
resolve({ json: () => response });
});
}
configure(func) {}
}
describe('Order', () => {
var sut, http, itemStubs, itemFake;
beforeEach(() => {
http = new HttpStub();
sut = new Order(http);
itemStubs = [1];
itemFake = [2];
http.itemStub = itemStubs;
});
describe('getOrders', () => {
it('should return orders', (done) => {
var info = new Info("1", "C", null, null);
sut.getOrders(info).then(result => {
expect(result).toBe(itemStubs);
expect(result).not.toBe(itemFake);
done();
});
});
});
});

Answer 1

Try using the jasmine spyOn function with callFake. Jasmine's spies are an easier way to mock a function call.
beforeEach(function () {
spyOn(httpClient, "fetch").and.callFake(function () {
return new Promise(function (resolve, reject) {
var fetchResponse = "the fake response";
resolve(fetchResponse);
});
});
});
An example (with TypeScript)
import { HttpClient } from "aurelia-fetch-client";
import { autoinject, Container } from "aurelia-framework";
#autoinject
export class DemoClass {
constructor(private httpClient: HttpClient) { }
public UseTheHttpClient() {
return this.httpClient.fetch("some_url");
}
}
describe("the demo class", function () {
let container: Container = new Container();
let httpClient: HttpClient = new HttpClient(); // create an http client
container.registerInstance(HttpClient, httpClient);
let demoClass: DemoClass = container.get(DemoClass);
beforeEach(function () { // spy on that HTTP client
spyOn(httpClient, "fetch").and.callFake(function () {
return new Promise(function (resolve, reject) {
resolve("some_fake_response");
});
});
});
it("returns the fake response", function (done) {
demoClass.UseTheHttpClient().then((response) => {
expect(response).toBe("some_fake_response");
done();
});
});
});