Tests

This document outlines the guidelines for writing tests.

Runners

We use Jest as our test runner and React Testing Library for testing React components.

Categories

We divide our tests into two categories: unit tests and e2e tests. Unit tests are for testing individual functions, and e2e tests are for testing the entire application.

We write unit tests in the tests/unit/tests folder and e2e tests in the tests/e2e/tests folder, both ending with the .test.ts or .test.tsx extension.

File Structure

The inital file structure for tests in your package should be as follows:

tests/
  e2e/
    tests/
      myFunction.test.ts
    babel.config.cjs
    jest.config.ts
  unit/
    tests/
      myOtherFunction.test.ts
    babel.config.cjs
    jest.config.ts
  tsconfig.json
jest.config.ts

Configuration

1. Follow the installation instructions from @ttoss/config to set up Jest.

2. Define the configuration for Jest in the jest.config.ts file at the root of the package. This configuration set up Jest projects.

   import { jestRootConfig } from '@ttoss/config';
   
   export default jestRootConfig();

3. For unit tests, create a jest.config.ts file in the tests/unit folder.

   import { jestUnitConfig } from '@ttoss/config';
   
   export default jestUnitConfig();

4. For e2e tests, create a jest.config.ts file in the tests/e2e folder.

   import { jestE2EConfig } from '@ttoss/config';
   
   export default jestE2EConfig();

5. Create a Babel configuration file in each test folder: tests/unit/babel.config.cjs and tests/e2e/babel.config.cjs. Jest needs Babel to transpile the code before running the tests.

   const { babelConfig } = require('@ttoss/config');
   
   const config = babelConfig({});
   
   module.exports = config;

6. Create a tsconfig.json file at tests/tsconfig.json with the following content:

   {
     "extends": "@ttoss/config/tsconfig.test.json",
     "compilerOptions": {
       "paths": {
         "src/*": ["../src/*"],
         "tests/*": ["./*"]
       }
     }
   }

   This way, you can import files from the src folder in your tests. For example:

   import { myFunction } from 'src/myFunction';

7. Add the following scripts to the package.json file:

   {
     "scripts": {
       "e2e": "jest --projects tests/e2e",
       "test": "jest --projects tests/unit"
     }
   }

8. Finnaly, write your tests in the tests/unit/tests and tests/e2e/tests folders.

9. Run the unit tests with the following command:

   pnpm test

   Or run only the e2e tests with:

   pnpm e2e