TNG - AI-Powered Test Generation for Rails

TNG automatically generates comprehensive tests for your Rails applications using static code analysis and AI. It analyzes your code structure, authentication patterns, and configuration to generate high-quality, contextual tests that follow your project's conventions.

Owner: Binary Dreams LLC

Add to your Gemfile:

gem 'tng'

Install:

bundle install

Generate the configuration file:

rails generate tng:install

This creates config/initializers/tng.rb with auto-detected settings for your Rails application.

Add your API key from https://app.tng.sh/ to your environment or configuration:

# .env
TNG_API_KEY=your_api_key_here

Or directly in config/initializers/tng.rb:

config.api_key = ENV["TNG_API_KEY"]

⚠️ IMPORTANT: You must configure your authentication methods for TNG to generate accurate tests.

Edit config/initializers/tng.rb and uncomment the authentication_methods section:

config.authentication_methods = [
  {
    method: "authenticate_user!",
    file_location: "app/controllers/application_controller.rb",
    auth_type: "devise"
  }
]

Interactive Mode (Recommended):

bundle exec tng

Direct Mode:

bundle exec tng app/controllers/users_controller.rb index

• Generate Tests: Browse and select files to generate tests for
• View Stats: See project statistics and test coverage
• System Status: Check configuration and system health
• About: View version and license information
• Exit: Quit the application

• Browse Files: Navigate through 20+ file types (controllers, models, services, jobs, helpers, mailers, GraphQL, etc.)
• Search: Find files quickly by name
• Filter: Filter by file type
• Select Methods: Choose specific methods to generate tests for
• Preview: Review generated tests before saving
• Pagination: Navigate through large file lists

• View Generated Test: Open the test file in your editor
• Run Test: Execute the test immediately
• Copy Test Command: Copy the test command to clipboard
• Generate Another: Continue testing other methods
• Back to Menu: Return to main menu

TNG can generate tests for 20+ Rails file types:

Edit config/initializers/tng.rb to customize test generation.

Test Frameworks:

Configuration:

TESTING_FRAMEWORK = "minitest"  # Options: minitest, rspec

Test Styles:

Assertion Styles:

Configuration:

TEST_STYLE = "test_block"          # Options: test_block, spec, unit
ASSERTION_STYLE = "assert/refute"  # Options: assert/refute, assert/assert_not, must/wont
SETUP_STYLE = true                 # Options: true, false
TEARDOWN_STYLE = false             # Options: true, false

Configuration:

DESCRIBE_STYLE = true          # Options: true, false
CONTEXT_STYLE = "context"      # Options: context, describe
IT_STYLE = "it"                # Options: it, specify
BEFORE_STYLE = "before"        # Options: before, setup
AFTER_STYLE = "after"          # Options: after, teardown
LET_STYLE = true               # Options: true, false
SUBJECT_STYLE = true           # Options: true, false

Mock Libraries:

HTTP Mock Libraries:

Factory Libraries:

Configuration:

MOCK_LIBRARY = "minitest/mock"      # Options: minitest/mock, mocha, rspec-mocks, flexmock, nil
HTTP_MOCK_LIBRARY = "webmock"       # Options: webmock, vcr, httparty, nil
FACTORY_LIBRARY = "factory_bot"     # Options: factory_bot, factory_girl, fabrication, fabricator, fixtures, active_record

Authentication Libraries:

Authorization Libraries:

Configuration:

AUTHENTICATION_ENABLED = true          # Options: true, false
AUTHENTICATION_LIBRARY = "devise"      # Options: devise, clearance, sorcery, nil
AUTHORIZATION_LIBRARY = "pundit"       # Options: cancancan, pundit, rolify, nil

TNG requires you to specify your authentication methods for accurate test generation:

config.authentication_methods = [
  {
    method: "authenticate_user!",              # The method name in your code
    file_location: "app/controllers/application_controller.rb",  # Where it's defined
    auth_type: "devise"                        # Authentication type
  }
]

Required Fields:

• method - The authentication method name (e.g., authenticate_user!, require_login)
• file_location - Path to the file where the method is defined
• auth_type - Type of authentication (see supported types below)

Supported auth_type Values:

• session - Session-based authentication
• devise - Devise gem
• jwt - JSON Web Token
• token_auth - Token-based authentication
• basic_auth - HTTP Basic Authentication
• oauth - OAuth authentication
• headers - Custom header authentication
• custom - Custom authentication logic

Examples:

Devise Authentication:

config.authentication_methods = [
  {
    method: "authenticate_user!",
    file_location: "app/controllers/application_controller.rb",
    auth_type: "devise"
  }
]

Session-Based Authentication:

config.authentication_methods = [
  {
    method: "require_login",
    file_location: "app/controllers/application_controller.rb",
    auth_type: "session"
  }
]

JWT Authentication:

config.authentication_methods = [
  {
    method: "authenticate_with_token",
    file_location: "app/controllers/api/base_controller.rb",
    auth_type: "jwt"
  }
]

Multiple Authentication Methods:

config.authentication_methods = [
  {
    method: "authenticate_user!",
    file_location: "app/controllers/application_controller.rb",
    auth_type: "session"
  },
  {
    method: "authenticate_api_user!",
    file_location: "app/controllers/api/base_controller.rb",
    auth_type: "token_auth"
  }
]

If You Don't Use Authentication:

config.authentication_enabled = false
config.authentication_methods = []

If your library or option isn't listed: TNG auto-detects most common configurations. Review and edit the generated config/initializers/tng.rb to match your specific setup.

READ_SOURCE_CODE = true   # Analyzes the file being tested
READ_TEST_CODE = true     # Reads existing tests to match your patterns

Launch the interactive UI:

bundle exec tng

Navigate through your application to select files and methods for test generation.

Generate tests directly from the command line:

# Full path with method
bundle exec tng app/controllers/users_controller.rb index

# Shorthand
bundle exec tng f=users_controller.rb m=show

# Long form
bundle exec tng --file=app/models/user.rb --method=validate

# From subdirectories (auto-detection)
bundle exec tng users_controller.rb index

Direct Mode Features:

• Automatic file type detection
• Flexible file path resolution
• Multiple syntax formats (f= or --file=)
• Smart path finding

Enable detailed logging:

# Interactive mode
DEBUG=1 bundle exec tng

# Direct mode
DEBUG=1 bundle exec tng app/controllers/users_controller.rb index

bundle exec tng --help
bundle exec tng -h

1. Static Analysis: TNG uses Rust-based static analysis to parse your Ruby code and extract:

   • Method signatures and parameters
   • Controller routes and actions
   • Model associations and validations
   • Database relationships
   • Authentication patterns
   • Service object patterns

2. Configuration Context: Reads your configuration to understand:

   • Testing framework preferences
   • Authentication/authorization setup
   • Factory and mock library choices
   • Existing test patterns

3. AI Generation: Sends analyzed data to TNG API, which uses LLMs to generate:

   • Contextual test cases
   • Proper setup/teardown
   • Authentication mocks
   • Database fixtures
   • Edge case coverage

4. Test Saving: Generates tests in the correct location (spec/ or test/) matching your framework conventions.

Error: "Invalid API key"

• Verify your API key from https://app.tng.sh/
• Check environment variable: echo $TNG_API_KEY
• Ensure no extra spaces in .env file

Error: "API key not found"

• Set environment variable: export TNG_API_KEY=your_key
• Or add to .env: TNG_API_KEY=your_key
• Restart Rails server after changes

Error: "Invalid configuration"

• Run: rails console then Tng.configuration
• Verify all required settings are present
• Check for typos in config/initializers/tng.rb

Poor Test Quality

• Verify authentication methods are correctly configured
• Check factory library setting matches your setup
• Ensure read_source_code and read_test_code are enabled
• Review testing framework settings

Tests don't include authentication

• Verify authentication_enabled = true
• Check authentication methods are correctly specified
• Ensure file paths exist: ls app/controllers/application_controller.rb
• Verify method names exist in specified files

Authentication tests fail

• Check auth method names match your application
• Verify file locations are correct
• Ensure auth_type matches your authentication pattern

No Tests Generated

1. Verify file path is correct: ls app/controllers/users_controller.rb
2. File contains valid Ruby code
3. Configuration is valid
4. API key is working
5. Internet connection is available

Generated Tests Are Generic

• Authentication not properly configured
• Factory library setting doesn't match your setup
• read_source_code or read_test_code disabled
• File analysis failed (check DEBUG mode)

Error: "Unsupported platform"

• Verify you're on macOS or Linux
• Check: uname -a
• TNG supports macOS (Intel/ARM) and Linux (Intel/ARM)

Error: "Binary not found"

• Ensure binaries are present: ls binaries/
• Reinstall gem: gem uninstall tng && gem install tng

Copyright (c) 2025 Binary Dreams LLC. All rights reserved.

See LICENSE.md for details.