Unit Testing Examples

// calculator.test.ts
import { expect, test } from 'vitest';
import { add } from './calculator.js';

test('adds two numbers', () => {
  // Arrange
  const a = 2;
  const b = 3;
  
  // Act
  const result = add(a, b);
  
  // Assert
  expect(result).toBe(5);
});

// button.svelte.test.ts
import { render } from 'vitest-browser-svelte';
import { page } from 'vitest-browser/context';
import { expect, test, vi } from 'vitest';
import Button from './button.svelte';

test('calls on_click when clicked', async () => {
  const on_click = vi.fn();
  render(Button, {
    props: { on_click }
  });
  
  const button = page.getByRole('button');
  await button.click();
  expect(on_click).toHaveBeenCalled();
});