Suites Examples

Real-world examples demonstrating Suites integration with popular dependency injection frameworks and test runners.

Each example showcases solitary and sociable testing patterns using the same user management domain model.

If you are new to Suites, check out the Getting Started guide.

Examples

Example	DI Framework	Test Runner	Use When
nestjs-jest	NestJS	Jest	NestJS with Jest
nestjs-vitest	NestJS	Vitest	NestJS with Vitest
nestjs-sinon	NestJS	Sinon	NestJS with Sinon/Mocha
inversify-jest	InversifyJS	Jest	InversifyJS with Jest
inversify-vitest	InversifyJS	Vitest	InversifyJS with Vitest
inversify-sinon	InversifyJS	Sinon	InversifyJS with Sinon/Mocha
advanced-mock-config	NestJS	Jest	Advanced .mock().final() and .impl() patterns

Quick Start

# Clone and run any example
cd nestjs-jest
pnpm install
pnpm test

All tests should pass immediately, demonstrating both testing strategies.

Testing Strategies

Each example demonstrates two approaches:

Solitary Unit Tests

const { unit, unitRef } = await TestBed.solitary(UserService).compile();

Test one class in complete isolation. All dependencies are replaced with test doubles.

When to use:

• Testing component logic in isolation
• Controlling all inputs for predictable results

Trade-off: Does not verify interactions between components

Sociable Unit Tests

const { unit, unitRef } = await TestBed.sociable(UserService)
  .expose(UserValidator) // Use real validator
  .expose(UserRepository) // Use real repository
  .compile();

Test multiple classes together with their real collaborators. External I/O (databases, APIs, file systems) is replaced with test doubles to keep tests fast.

When to use:

• Verifying components work together correctly
• Testing interactions between business logic components

Trade-off: Slower execution, multiple failure points

Both strategies are unit tests - they keep external I/O mocked and remain fast. Use both together for comprehensive coverage.

What Each Example Demonstrates

• Solitary unit tests - Test one class in complete isolation with all dependencies mocked
• Sociable unit tests - Test multiple classes together with real collaborators, external I/O mocked
• Type-safe mocking - Full TypeScript support without manual setup
• Zero boilerplate - No test module configuration required

Common Use Case

All examples implement the same user management service with three key components:

graph LR
    UserService --> UserValidator
    UserService --> UserRepository
    UserRepository --> DATABASE_TOKEN

Loading

• UserService - Business logic layer with validation and persistence
• UserValidator - Email validation (no dependencies)
• UserRepository - Data access layer (depends on database token)

This consistent domain model makes it easy to compare different framework and test runner combinations.

Repository Structure

examples/
├── nestjs-jest/          # NestJS with Jest
├── nestjs-vitest/        # NestJS with Vitest
├── nestjs-sinon/         # NestJS with Sinon
├── inversify-jest/       # InversifyJS with Jest
├── inversify-vitest/     # InversifyJS with Vitest
├── inversify-sinon/      # InversifyJS with Sinon
└── advanced-mock-config/ # Advanced .mock().final() and .impl() patterns

Each example contains two directories:

src/ - Application code being tested:

• types.ts - Domain types and interfaces
• user.service.ts - Business logic layer
• user.validator.ts - Validation logic
• user.repository.ts - Data access layer

tests/ - Tests demonstrating Suites usage:

• user.solitary.spec.ts - Solitary unit tests (all dependencies mocked)
• user.sociable.spec.ts - Sociable unit tests (real collaborators, external I/O mocked)

Prerequisites

• Node.js 18 or higher
• pnpm installed globally
• Basic understanding of TypeScript and dependency injection

Troubleshooting

Tests fail after install

1. Check Node.js version: node --version (requires 18+)
2. Check pnpm: pnpm --version
3. Clear and reinstall: rm -rf node_modules && pnpm install
4. Verify working directory is the example directory, not repository root

"reflect-metadata" errors (InversifyJS examples)

InversifyJS requires decorator metadata. Configuration is already set in tsconfig.json and imports. If errors occur, verify:

• experimentalDecorators: true in tsconfig.json
• emitDecoratorMetadata: true in tsconfig.json
• import 'reflect-metadata' at top of test files

Sinon tests show different output format

Sinon uses Mocha test runner, which formats output differently than Jest/Vitest. All examples show 6 passing tests.

"Module not found" errors

Run pnpm install in the specific example directory. Each example has standalone dependencies.

Learn More

• Suites Documentation
• Testing Strategies Guide
• NestJS Integration
• InversifyJS Integration