@nativescript/unit-test-runner

Run Vitest unit and UI tests inside real NativeScript runtimes on Android, iOS, and visionOS.

Vitest stays on your machine as the orchestrator — configuration, CLI, reporters, --ui, coverage, and editor integrations all work as usual — while your specs execute on device/emulator inside the actual V8/JSC runtimes, with full access to native APIs and the NativeScript UI layer.

Version 5 is a complete rewrite. Karma-based testing (v4 and below) is deprecated; see the migration guide.

Quick start

ns test init --framework vitest
ns test ios       # or: ns test android / ns test visionos

Or run Vitest directly (what editor extensions and CI use):

NS_PLATFORM=ios npx vitest run

How it works

• A Vitest plugin installs a custom pool that forwards Vitest's standard worker protocol over a WebSocket bridge (bound to 127.0.0.1).
• The plugin launches your app via ns run <platform> --no-hmr --env.unitTesting; the webpack helper (auto-discovered from this package) swaps the bundle entry to your test.ts for test builds only.
• On device, a coordinator connects back to the host and executes specs:
  • Main-thread context (default): specs run on the UI thread, so they can create Views, navigate Frames, and use every NativeScript API.
  • Worker contexts (opt-in): additional isolated NativeScript Worker runtimes for parallel, non-UI specs.
• Results flow through Vitest's normal RPC, so every reporter works unchanged.

Configuration

// vitest.config.mts
import { defineConfig } from 'vitest/config';
import { nativeScript } from '@nativescript/unit-test-runner';

export default defineConfig({
  plugins: [
    nativeScript({
      platform: process.env.NS_PLATFORM || 'ios', // 'android' | 'ios' | 'visionos'
      device: process.env.NS_DEVICE || undefined,
      // workers: 2,          // extra Worker runtimes for non-UI specs
      // mainThread: false,   // disable the UI-capable slot (workers only)
      // port: 17878,
      // launch: false,       // attach to an app you run yourself
    }),
  ],
});

Per-platform setups are possible with Vitest projects — give each project its own nativeScript({ platform }) plugin instance.

UI testing

import { describe, expect, it } from 'vitest';
import { Button } from '@nativescript/core';
import { mount, tap } from '@nativescript/unit-test-runner/testing';

describe('counter button', () => {
  it('increments on tap', async () => {
    let count = 0;
    const { view } = await mount(() => {
      const button = new Button();
      button.text = 'Count';
      button.on('tap', () => (count += 1));
      return button;
    });

    await tap(view);
    expect(count).toBe(1);
    expect(view.isLayoutValid).toBe(true);
  });
});

mount() attaches the view to the host page scaffolded in your test.ts, waits for loaded + a real layout pass, and auto-unmounts when the test finishes. Also available from ./testing: tap, doubleTap, longPress, enterText, returnPress, waitForLayout, waitUntil, nextRenderPass.

UI specs require the main-thread context (the default). Files routed to Worker contexts must not touch Views.

Coverage

ns test ios --env.codeCoverage
# or: NS_PLATFORM=ios npx vitest run --coverage

Use the istanbul provider — device runtimes do not expose V8 coverage:

test: {
  coverage: { provider: 'istanbul', reporter: ['text', 'lcov'] },
},

Devices and networking

Target	Transport
iOS / visionOS simulator	host loopback (127.0.0.1)
Android emulator	10.0.2.2 → host loopback
Physical Android	USB via automatic adb reverse
Physical iOS / Apple Vision Pro	pass a LAN-reachable url to the coordinator in test.ts

The host server binds 127.0.0.1 by default. Test builds on Android may need a scoped cleartext exception for 10.0.2.2/127.0.0.1; on iOS and visionOS, NSAllowsLocalNetworking.

Support matrix

Feature	Status
describe / it / hooks / expect	✅
Reporters, vitest --ui, JUnit output	✅
Istanbul coverage	✅
UI testing (mount, gestures)	✅ main-thread context
vi.fn / vi.spyOn / fake timers	🚧 planned
Snapshots	🚧 planned
Watch mode	🚧 planned (one-shot vitest run today)
vi.mock module mocking	❌ not supported (webpack static bundle) — prefer DI

Credits

The host↔device bridge design originates from @cross-code/vitest-ns by @listepo (MIT). Thank you!

License

Apache-2.0