the de-facto standard for unit testing Java applications

spying objects/dependencies framework

a more powerful Mockito

for stubbing out external services

a fluent assertion library

a library of matcher objects (also known as constraints or predicates)

an assertion library for JSON

XPath for JSON

for writing Consumer-Driven Contracts (CDC) tests

for writing UI-driven end-to-end tests

for writing REST API-driven end-to-end tests

for using Docker containers within tests

for performance/micro-benchmark testing

utilities and integration test support for Spring Boot applications