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.

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

Follow the installation instructions from @ttoss/config to set up Jest.
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();
```

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

import { jestUnitConfig } from '@ttoss/config';

export default jestUnitConfig();

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

import { jestE2EConfig } from '@ttoss/config';

export default jestE2EConfig();

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;
```

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';

Add the following scripts to the package.json file:

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

Finnaly, write your tests in the tests/unit/tests and tests/e2e/tests folders.
Run the unit tests with the following command:
```
pnpm test
```
Or run only the e2e tests with:
```
pnpm e2e
```

Test Coverage Requirements

Minimum Coverage Baseline

All packages must maintain minimum 10% test coverage as a baseline requirement. This ensures basic testing discipline while remaining achievable for all team members.

Coverage Improvement Strategy

Package-specific goals: Each package can set higher coverage targets based on complexity and criticality
Incremental improvement: Increase coverage gradually when the team has capacity
Flexible timeline: No rigid schedule—improve when sustainable for the team
Focus on critical paths: Prioritize testing of core functionality and user flows

Coverage Tracking

Monitor coverage using Jest's built-in coverage reporting:

# Generate coverage report
pnpm test -- --coverage

# Set coverage thresholds in jest.config.ts
export default {
  coverageThreshold: {
    global: {
      lines: 10,
      functions: 10,
      branches: 10,
      statements: 10,
    },
  },
};

Integration with Pull Requests

Baseline maintenance: PRs should not decrease overall package coverage below 10%
New feature testing: New features should include appropriate test coverage
Coverage reporting: Use coverage reports to guide testing priorities

Runners​

Categories​

File Structure​

Configuration​

Test Coverage Requirements​

Minimum Coverage Baseline​

Coverage Improvement Strategy​

Coverage Tracking​

Integration with Pull Requests​