k6-testing

A seamless way to write functional tests in k6 with Playwright-compatible assertions.

⚠️ Note: This is a prototype project demonstrating the concept. Not yet ready for production use.

Why k6-testing?

• ✨ Write once, run anywhere: Copy-paste your Playwright test assertions directly into k6 - they'll work out of the box
• 🎯 Fail fast: Tests interrupt immediately when assertions fail, giving you quick, clear feedback
• 🔄 Progressive API: Start simple with assert, scale up to expressive expect assertions as your needs grow
• 🎭 Familiar API: Familiar API for anyone coming from Playwright, Deno, or Vite ecosystem
• 🔍 Clear error messages: Get detailed, actionable feedback when tests fail

Installation

deno task build

Quick Start

import { expect } from "https://github.com/oleiade/k6-testing/releases/download/v0.1.0/index.js";

export default function () {
  // Simple assertions
  expect(response.status).toBe(200);
  
  // Async assertions with retry (perfect for UI testing)
  await expect(page.locator('.submit-button')).toBeEnabled();
  
  // Soft assertions - continue testing even after failures
  expect.soft(data.userId).toBeDefined();
}

Features

1. Playwright-Compatible Expectations

Use the same assertions you know from Playwright:

// These Playwright assertions work exactly the same in k6
await expect(page.locator('.button')).toBeVisible();
await expect(page.locator('input')).toHaveValue('test');

2. Retrying Assertions

Perfect for UI testing, these assertions automatically retry until they pass or timeout:

3. Standard Assertions

For immediate validation without retry:

4. Soft Assertions

Keep tests running even after failures - perfect for collecting multiple failures in one run:

// Test continues even if assertions fail
expect.soft(response.status).toBe(200);
expect.soft(data.items).toHaveLength(5);

5. Basic Assertions

Low-level assertions for simple cases:

import { assert, assertEquals } from "k6-testing";

assert(condition, "error message");
assertEquals(actual, expected, "error message");

Progressive Testing Approach

k6-testing offers multiple layers of assertion capabilities:

1. Basic: Start with simple assert() for straightforward checks
2. Standard: Use expect() for more expressive assertions
3. Advanced: Leverage retrying assertions for robust UI testing
4. Comprehensive: Combine with soft assertions for thorough test coverage

Error Handling

Get clear, actionable error messages:

expect(value).toBe(expected);
// Error: Expected value to be undefined
//   Expected: undefined
//   Received: "actual value"

Contributing

Contributions are welcome! Check out our Contributing Guide for details.

License

MIT License