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Test Double Libraries

Libraries providing test spies, stubs, and mocks that help developers simulate and verify behavior in unit tests.

42 projects

66,610 contributors

$215M

Jest

Jest is a comprehensive JavaScript testing framework focused on simplicity and developer experience. It provides a complete testing solution with built-in assertion libraries, mocking capabilities, snapshot testing, and code coverage reporting. The framework is designed to work with most JavaScript projects, including React applications, with minimal configuration required.

Contributors

16,333

Organizations

4,683

Software value

$5.8M

Moto

Moto is a Python library that mocks AWS services for testing and development purposes. It allows developers to easily test their AWS applications by providing mock implementations of AWS APIs, enabling offline development and testing without incurring actual AWS costs.

Contributors

4,624

Organizations

965

Software value

$127M

Enzyme

JavaScript Testing utilities for React

Contributors

4,376

Organizations

1,244

Software value

$1.1M

Robolectric

Robolectric is a testing framework for Android applications that allows tests to run directly on the JVM without requiring an Android device or emulator. It provides a simulated Android environment and enables fast, reliable unit testing of Android code by replacing Android SDK dependencies with shadow objects.

Contributors

4,274

Organizations

659

Software value

$11M

PHPUnit

PHPUnit is a widely-used testing framework for PHP that enables developers to write and run automated unit tests. It provides a comprehensive suite of testing tools, assertions, and test runners to validate PHP code functionality and ensure software quality.

Contributors

3,816

Organizations

1,333

Software value

$4.2M

Faker Ruby

Faker is a Ruby library for generating realistic fake data like names, addresses, phone numbers, and other types of test data. It helps developers create sample data for testing, seeding databases, and building example datasets.

Contributors

2,991

Organizations

751

Software value

$13M

RSpec Rails

RSpec Rails is a testing framework that brings RSpec's behavior-driven development approach to Ruby on Rails applications, providing a domain-specific language for writing readable, maintainable tests and specifications for Rails components

Contributors

2,792

Organizations

1,014

Software value

$571K

Mockito

Mockito is a popular mocking framework for Java unit testing that allows creating and configuring mock objects. It enables developers to write clean tests by mocking dependencies and verifying behavior in an elegant way.

Contributors

2,634

Organizations

555

Software value

$2.3M

Sinon.JS

Sinon.JS is a standalone test spies, stubs and mocks library for JavaScript. It provides test doubles that can be used with any unit testing framework to help verify and validate behavior of JavaScript applications.

Contributors

2,293

Organizations

811

Software value

$1.1M

React Testing Library

React Testing Library is a lightweight testing utility for React that encourages good testing practices by working with actual DOM nodes and simulating user interactions rather than dealing with component instances. It helps developers write maintainable tests that closely resemble how users interact with their applications.

Contributors

2,097

Organizations

593

Software value

$116K

factory_bot

A library for setting up Ruby objects as test data.

Contributors

2,097

Organizations

743

Software value

$452K

Testify

Testify is a testing and assertion toolkit for Go that provides a rich set of assertion functions and testing utilities to make writing tests easier and more expressive

Contributors

2,009

Organizations

785

Software value

$659K

Nock

Nock is an HTTP server mocking and expectations library for Node.js that allows intercepting HTTP requests and providing mock responses for testing purposes

Contributors

1,699

Organizations

642

Software value

$528K

DOM Testing Library

🐙 Simple and complete DOM testing utilities that encourage good testing practices.

Contributors

1,292

Organizations

402

Software value

$321K

WebMock

WebMock is a library for stubbing and setting expectations on HTTP requests in Ruby. It allows developers to disable real HTTP requests and simulate responses for testing purposes, supporting features like request matching, response stubbing, and request verification.

Contributors

1,260

Organizations

493

Software value

$474K

Faker

Faker is a popular open source library for generating fake data like names, addresses, phone numbers and other types of test data for software development and testing purposes. It helps developers create realistic sample data for testing, seeding databases, and building demos.

Contributors

1,247

Organizations

282

Software value

$9.2M

Mockery

Mockery is a simple yet flexible PHP mock object framework for use in unit testing with PHPUnit, PHPSpec or any other testing framework. Its core goal is to offer a test double framework with a succinct API capable of clearly defining all possible object operations and interactions using a human readable Domain Specific Language (DSL).

Contributors

1,122

Organizations

369

Software value

$3.7M

Testcontainers for Go

Testcontainers for Go is a testing library that provides lightweight, throwaway instances of common databases, message brokers, and other services in Docker containers for use in automated tests. It enables developers to write integration tests that run against real dependencies rather than mocks, while maintaining test isolation and reproducibility.

Contributors

1,108

Organizations

384

Software value

$2.2M

factory_boy

A Python library for generating test data and fixtures using factories. It provides a flexible way to create complex objects for testing purposes, with support for sequences, sub-factories, and various data generation strategies.

Contributors

1,086

Organizations

398

Software value

$418K

GoMock

GoMock is a mocking framework for the Go programming language that helps developers write unit tests by generating mock implementations of interfaces. It provides a flexible way to create mock objects for testing code that depends on interfaces.

Contributors

745

Organizations

300

Software value

$241K

Alice

Alice is a PHP library for generating fixture data, allowing developers to create random yet realistic test data using a YAML-based expressive syntax. It supports object population, references between fixtures, and customizable data generation.

Contributors

700

Organizations

217

Software value

$1.5M

NSubstitute

A friendly substitute for .NET mocking libraries.

Contributors

687

Organizations

136

Software value

$789K

factory_bot_rails

A Ruby gem that provides Rails integration for factory_bot, enabling the creation of test data and fixtures through factories rather than hard-coded test data. It helps developers write cleaner and more maintainable tests by providing a straightforward way to set up test data.

Contributors

674

Organizations

265

Software value

$48K

Responses

A utility for mocking out the Python Requests library.

Contributors

664

Organizations

243

Software value

$215K

Bogus

Bogus is a simple and sane fake data generator for .NET languages like C#, F#, and VB.NET. It helps developers create realistic test data by generating names, addresses, phone numbers, and other types of mock data in a clean, readable way.

Contributors

524

Organizations

95

Software value

$5.5M

Datafaker

Datafaker is a Java library that generates fake data for testing and development purposes. It provides a wide range of data generators for names, addresses, numbers, dates, and other types of data, helping developers create realistic test datasets.

Contributors

517

Organizations

72

Software value

$8.3M

FakeFS

A fake filesystem. Use it in your tests.

Contributors

437

Organizations

181

Software value

$242K

Verify

Verify is a snapshot testing tool for .NET that helps verify complex objects and documents by capturing their state as human-readable files. It supports multiple output formats, handles complex object comparisons, and integrates with popular testing frameworks.

Contributors

392

Organizations

119

Software value

$6M

eslint-plugin-testing-library

ESLint plugin that provides rules for testing-library, helping developers follow best practices when writing tests using Testing Library tools and utilities

Contributors

370

Organizations

118

Software value

$919K

MSW Interceptors

Low-level network interception library.

Contributors

348

Organizations

132

Software value

$684K

Zenstruck Foundry

A model factory library for creating expressive, auto-completable, on-demand dev/test fixtures with Symfony and Doctrine.

Contributors

322

Organizations

89

Software value

$667K

Sinon.js Fake Timers

A JavaScript library that provides utilities for faking and manipulating timers, enabling precise control over time-dependent code during testing by allowing developers to simulate passage of time, schedule events, and manage timer-based functions

Contributors

299

Organizations

133

Software value

$254K

ApprovalTests.Java

ApprovalTest verification library for Java

Contributors

197

Organizations

46

Software value

$1.3M

EasyMock

EasyMock, makes mocking easier since 2001

Contributors

190

Organizations

53

Software value

$3.5M

ApprovalTests.Python

ApprovalTests.Python is a testing library that helps verify complex objects and scenarios by taking a snapshot of the results and managing them as approved files. It simplifies testing by allowing developers to approve changes to test outputs rather than writing explicit assertions.

Contributors

174

Organizations

28

Software value

$355K

RR

RR is a test double framework that features a rich selection of double techniques and a terse syntax. ⛺

Contributors

115

Organizations

38

Software value

$414K

python-dbusmock

A Python library for mocking D-Bus interfaces, allowing developers to create mock D-Bus objects and services for testing applications without requiring actual D-Bus services to be running

Contributors

105

Organizations

41

Software value

$272K

Freerange Mocha: Ruby Mocking and Stubbing Library

A mocking and stubbing library for Ruby

This project hasn't been onboarded to LFX Insights.

Nise

Fake XHR and fake server

This project hasn't been onboarded to LFX Insights.
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