Jest Test Framework

Jest Test Framework

Purpose

Provide comprehensive Jest test execution and generation capabilities for JavaScript and TypeScript projects, supporting:

• Test file generation from bug reports
• Test execution with detailed output parsing
• Unit, integration, and E2E test patterns
• TypeScript and modern JavaScript syntax

Usage

Generate Test File

Create a test file from a bug report or feature description:

node generate-test.js \
  --source src/​components/​Button.js \
  --output tests/​components/​Button.test.js \
  --type unit \
  --description "Button component fails to handle click events"

Execute Tests

Run Jest tests and return structured results:

node run-test.js \
  --file tests/​components/​Button.test.js \
  --config jest.config.js

Command Line Options

generate-test.js

• --source <path> - Source file to test (required)
• --output <path> - Output test file path (required)
• --type <unit|integration|e2e> - Test type (default: unit)
• --description <text> - Bug description or test purpose
• --framework <react|node|express> - Framework-specific patterns

run-test.js

• --file <path> - Test file to execute (required)
• --config <path> - Jest config file (optional)
• --coverage - Run with coverage report
• --watch - Run in watch mode (not recommended for CI)

Output Format

Test Generation

Returns JSON with generated test file information:

{
  "success": true,
  "testFile": "tests/​components/​Button.test.js",
  "testCount": 3,
  "template": "unit-test",
  "framework": "react"
}

Test Execution

Returns JSON with test results:

{
  "success": false,
  "passed": 2,
  "failed": 1,
  "total": 3,
  "duration": 1.234,
  "failures": [
    {
      "test": "Button handles click events",
      "error": "Expected onClick to be called",
      "file": "tests/​components/​Button.test.js",
      "line": 15
    }
  ]
}

Templates

Unit Test Template

For testing individual functions or components in isolation:

• Minimal dependencies
• Fast execution
• Focused on single responsibility

Integration Test Template

For testing multiple components working together:

• Real dependencies (minimal mocking)
• Database/​API integration
• Multi-component workflows

E2E Test Template

For testing complete user journeys:

• Full application stack
• Browser automation (if applicable)
• End-to-end scenarios

Framework-Specific Patterns

React Components

import { render, fireEvent, screen } from '@testing-library/​react';
import { Button } from '../​components/​Button';

describe('Button', () => {
  it('handles click events', () => {
    const onClick = jest.fn();
    render(<Button onClick={onClick}>Click me</​Button>);
    fireEvent.click(screen.getByText('Click me'));
    expect(onClick).toHaveBeenCalled();
  });
});

Node.js/​Express

const request = require('supertest');
const app = require('../​app');

describe('GET /​api/​users', () => {
  it('returns list of users', async () => {
    const res = await request(app).get('/​api/​users');
    expect(res.status).toBe(200);
    expect(res.body).toBeInstanceOf(Array);
  });
});

Integration with deep-debugger

The deep-debugger agent uses this skill for:

1. Test Recreation: Generate failing test from bug report
2. Test Validation: Execute test to verify it fails consistently
3. Fix Verification: Re-run test after fix to ensure it passes

Example workflow:

1. deep-debugger receives bug report
2. Invokes test-detector to identify Jest
3. Invokes jest-test/​generate-test.js to create failing test
4. Invokes jest-test/​run-test.js to validate test fails
5. Delegates fix to appropriate specialist agent
6. Invokes jest-test/​run-test.js to verify fix

Dependencies

Requires Jest to be installed in the project:

npm install --save-dev jest @types/​jest

For React testing:

npm install --save-dev @testing-library/​react @testing-library/​jest-dom

Error Handling

Test Generation Errors

{
  "success": false,
  "error": "Source file not found",
  "file": "src/​components/​Missing.js"
}

Test Execution Errors

{
  "success": false,
  "error": "Jest configuration not found",
  "config": "jest.config.js"
}

See Also

• REFERENCE.md - Detailed Jest API reference and best practices
• templates/ - Test file templates for different scenarios