Testing

Testing is a critical part of the software development process, ensuring the reliability and maintainability of your React application. This section provides an overview of writing tests using Vitest, along with additional frameworks like React Testing Library for different types of tests: snapshot, unit, and browser testing. This section also covers debugging techniques for broken or failed tests and best practices for effective test writing.

Running Tests

Run tests with the following command: npm test

Writing Unit Tests

Unit tests focus on testing individual components or functions in isolation.

1. Basic Unit Test:

   import {
     fullNameValidators,
     emailValidators,
     phoneNumberValidators,
     cityValidators,
     stateValidators,
     zipcodeValidators,
   } from "../../utilities";
   
   test("should validate a correct email format", () => {
     expect(emailValidators[0].test("example@test.com")).toBe(true);
   });

2. Testing User Interactions:

   Utilize user-event or fireEvent from React Testing Library to simulate user actions.

   import { userEvent } from "@vitest/browser/context";
   import { screen } from "@testing-library/dom";
   
   test("triggers a double click on an element", async () => {
     const logo = screen.getByRole("img", { name: /logo/ });
   
     await userEvent.dblClick(logo);
   });

Writing Browser Tests

Browser testing involves testing the application in a web browser environment. Tools like Puppeteer can be used alongside Vitest. Please note Puppeteer does not come included by default in the RADFish framework.

1. Basic Browser Test:

   const puppeteer = require("puppeteer");
   
   it("should display the homepage", async () => {
     const browser = await puppeteer.launch();
     const page = await browser.newPage();
     await page.goto("http://localhost:3000");
     await expect(page.title()).resolves.toMatch("Home Page");
     await browser.close();
   });

Additional Vitest Configuration

Vitest and React Testing Library is included in the RADFish framework by default. Modifying the Vitest test configuration can be configured in the vite.config.js file. Please see the official Vitest docs for the latest configuration options: https://vitest.dev/config/.

Debugging Broken or Failed Tests

1. Review Test Output: Vitest provides detailed error messages. Analyze them to understand the failure.
2. Use console.log: Temporarily add console.log statements within your test to inspect values.
3. Check for Async Issues: Ensure promises are resolved and state updates are completed.

Best Practices

1. Descriptive Test Names: Clearly describe what each test is checking.
2. Small and Focused Tests: Write tests that cover single functionalities.
3. Avoid Over-Mocking: Use mocks sparingly to ensure tests remain close to real-world scenarios.
4. Test User Interactions: Simulate how users interact with your application.
5. Continuous Integration: Integrate testing into your CI/CD pipeline for regular feedback.

Effective testing in React using Vitest and related frameworks is key to building robust applications. By following this section and adhering to best practices, you can ensure your React components work as expected and are maintainable over time. Remember, the goal of testing is not just to find bugs, but to build confidence in your codebase.

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