K6.md

K6

K6 is a popular open-source performance testing tool for load testing APIs, microservices, and web applications. While K6 itself is not a .NET-specific tool, it can still be used to test .NET applications by targeting their APIs or web endpoints.

To use K6 with a .NET application, you'll need to install K6 and write test scripts in JavaScript. K6 test scripts define virtual users, scenarios, and performance metrics to be measured during the test execution. While K6 cannot directly interact with .NET code, it can still test the application's performance by sending HTTP requests and measuring the response times, throughput, and error rates.

Here's an example of using K6 to create a performance test for a hypothetical e-commerce API built with .NET:

1. The API has endpoints for listing products, searching for products, and fetching product details.
2. The performance test should simulate user traffic patterns, such as browsing products, searching for specific items, and viewing product details.

First, install K6 following the instructions on the official website: https://k6.io/docs/getting-started/installation/

Next, create a new JavaScript file (e.g., ecommerce-api-test.js) and write the K6 test script:

import http from 'k6/http';
import { sleep, check } from 'k6';

export let options = {
  stages: [
    { duration: '1m', target: 50 }, // Ramp up to 50 virtual users over 1 minute
    { duration: '3m', target: 50 }, // Maintain 50 virtual users for 3 minutes
    { duration: '1m', target: 0 },  // Ramp down to 0 virtual users over 1 minute
  ],
};

export default function () {
  // Simulate browsing products
  const browseProductsResponse = http.get('https://api.example.com/products');
  check(browseProductsResponse, {
    'Browse products: status is 200': (r) => r.status === 200,
  });

  // Simulate searching for products
  const searchProductsResponse = http.get('https://api.example.com/products/search?query=gaming+laptop');
  check(searchProductsResponse, {
    'Search products: status is 200': (r) => r.status === 200,
  });

  // Simulate fetching product details (assuming a specific product ID)
  const productDetailsResponse = http.get('https://api.example.com/products/1');
  check(productDetailsResponse, {
    'Fetch product details: status is 200': (r) => r.status === 200,
  });

  sleep(1);
}

This K6 test script performs the following actions:

1. Defines a test scenario with stages that ramp up, maintain, and ramp down the number of virtual users.
2. Sends HTTP requests to the e-commerce API's endpoints for browsing products, searching for products, and fetching product details.
3. Uses checks to validate that the API returns the expected HTTP status codes (200).
4. Adds a sleep function to introduce a delay between iterations, simulating user think time.

To run the test, execute the following command in the terminal:

k6 run ecommerce-api-test.js

K6 will execute the test scenario and display the performance metrics, such as response times, throughput, and error rates, in the terminal. You can also use K6's built-in options for outputting the results to different formats or integrating with monitoring and visualization tools, such as Grafana or Datadog.

In this example, K6 allows you to create performance tests that simulate real-world scenarios and measure the performance of your .NET application's API. While K6 does not directly interact with .NET code, it can effectively test the performance of your .NET application by targeting its APIs or web endpoints. By simulating realistic user scenarios and measuring key performance metrics, K6 can help you identify and address performance bottlenecks and ensure that your application meets the required performance standards.

In summary, K6 is a versatile and powerful tool for performance testing .NET applications, even though it's not .NET-specific. By writing test scripts that simulate real-world user scenarios and sending HTTP requests to your application's APIs or web endpoints, you can gain valuable insights into your application's performance and identify areas for improvement.