angular-testing

Angular Testing

Test Angular v20+ applications with Vitest (recommended) or Jasmine, focusing on signal-based components and modern patterns.

Vitest Setup (Angular v20+)

Angular v20+ has native Vitest support through the @angular/build package.

npm install -D vitest jsdom

Configure in angular.json:

{
  "projects": {
    "your-app": {
      "architect": {
        "test": {
          "builder": "@angular/build:unit-test",
          "options": {
            "tsConfig": "tsconfig.spec.json",
            "buildTarget": "your-app:build"
          }
        }
      }
    }
  }
}

Run tests:

ng test              # Run tests
ng test --watch      # Watch mode
ng test --code-coverage  # With coverage

For Vitest migration from Jasmine and advanced configuration, see references/vitest-migration.md.

Basic Component Test

import { describe, it, expect, beforeEach } from 'vitest';
import { ComponentFixture, TestBed } from '@angular/core/testing';
import { Counter } from './counter.component';

describe('Counter', () => {
  let component: Counter;
  let fixture: ComponentFixture<Counter>;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [Counter], // Standalone component
    }).compileComponents();

    fixture = TestBed.createComponent(Counter);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });

  it('should increment count', () => {
    expect(component.count()).toBe(0);
    component.increment();
    expect(component.count()).toBe(1);
  });

  it('should display count in template', () => {
    component.count.set(5);
    fixture.detectChanges();

    const element = fixture.nativeElement.querySelector('.count');
    expect(element.textContent).toContain('5');
  });
});

Testing Signals

Direct Signal Testing

import { signal, computed } from '@angular/core';

describe('Signal logic', () => {
  it('should update computed when signal changes', () => {
    const count = signal(0);
    const doubled = computed(() => count() * 2);

    expect(doubled()).toBe(0);

    count.set(5);
    expect(doubled()).toBe(10);

    count.update(c => c + 1);
    expect(doubled()).toBe(12);
  });
});