How to implement unit tests in NativeScript using TestBed and Jasmine?

To use TestBed you have to alter your karma.conf.js to:

    // list of files / patterns to load in the browser    files: [      'src/tests/setup.ts',      'src/tests/**/*.spec.ts'    ],

The file src/tests/setup.ts should look like this for jasmine:

import "nativescript-angular/zone-js/testing.jasmine";import {nsTestBedInit} from "nativescript-angular/testing";nsTestBedInit();

or if using mocha:

import "nativescript-angular/zone-js/testing.mocha";import {nsTestBedInit} from "nativescript-angular/testing";nsTestBedInit();

You'll find a sample here: https://github.com/hypery2k/tns_testbed_sample

I was facing the same issue like you. I finally found a way to make Unit Test in Nativescript-Angular works.

To fix my issue I add beforeAll(() => nsTestBedInit()); and afterAll(() => { });Also change from TestBed to nsTestBed...I just follow the idea on https://github.com/NativeScript/nativescript-angular/blob/master/tests/app/tests/detached-loader-tests.ts

Also add into tsconfig.tns.json file this line:"include": ["src/tests/*.spec.ts"],

My issue now is split all test into multiple file. Like appComponent in a test fileand homeCompenent in a second test file. When the app grow the unit test also grow, we need organize our code.

Here my code (file name: src/tests/test.spec.ts):

    import "reflect-metadata";    import { AppComponent } from "../app/app.component";    import { nsTestBedBeforeEach, nsTestBedAfterEach, nsTestBedRender, nsTestBedInit }     from "nativescript-angular/testing";    import { HomeComponent } from "@src/app/home/home.component";    describe("AppComponent", () => {        beforeAll(() => nsTestBedInit());        afterAll(() => { });        beforeEach(nsTestBedBeforeEach([AppComponent, HomeComponent]));        afterEach(nsTestBedAfterEach());        it("should be: app works!", () => {            return nsTestBedRender(AppComponent).then((fixture) => {                fixture.detectChanges();                const app = fixture.componentInstance;                expect(app.title).toBe("app works!");            });        });        describe("HomeComponent", () => {             it("should contain: Home works!", () => {              return nsTestBedRender(HomeComponent).then((fixture) => {                  fixture.detectChanges();                  const app = fixture.componentInstance;                  expect(app.title).toBe("Home works!");              });            });        });    });

And here the result:

JS: NSUTR: downloading http://192.168.10.169:9876/context.jsonJS: NSUTR: eval script /base/node_modules/jasmine-core/lib/jasmine-core/jasmine.js?be3ff9a5e2d6d748de5b900ac3c6d9603e2942a7JS: NSUTR: eval script /base/node_modules/karma-jasmine/lib/boot.js?945a38bf4e45ad2770eb94868231905a04a0bd3eJS: NSUTR: eval script /base/node_modules/karma-jasmine/lib/adapter.js?3098011cfe00faa2a869a8cffce13f3befc1a035JS: NSUTR: eval script /base/src/tests/test.spec.bundle.js?6e0098824123f3edc2bb093fa874b3fdf268841eJS: NSUTR: beginning test runNativeScript / 28 (9; Android SDK built for x86): Executed 1 of 2 SUCCESS (0 secs / 0.545 secs)NativeScript / 28 (9; Android SDK built for x86): Executed 2 of 2 SUCCESS (0.829 secs / 0.735 secs)TOTAL: 2 SUCCESSJS: NSUTR: completeAckNativeScript / 28 (9; Android SDK built for x86) ERROR  DisconnectedClient disconnected from CONNECTED state (transport error)NativeScript / 28 (9; Android SDK built for x86): Executed 2 of 2 SUCCESS (0.829 secs / 0.735 secs)

Your issue is happening because of these lines.

beforeAll(() => nsTestBedInit()); afterAll(() => { });

Each test file tries to initialize test bed. Make sure that you initialize it in your entry component.

Please refer entry file test-main.ts specified in karma.config.js