Kotest vs Pest

Kotest is a Kotlin testing framework for JVM and Kotlin Multiplatform projects, with test styles, assertions and property testing. Its styles allow natural-language test names and unlimited nesting. The DSL supports parameterized and data-driven tests, conditional evaluation, lifecycle callbacks and parallel execution. The assertion library includes over 350 matchers, collection inspectors, soft assertions and utilities for non-deterministic code. Property tests can generate hundreds or thousands of inputs, and property testing is supported across all targets. Listed targets include JVM, JavaScript, Native, Wasm and Android unit and instrumented tests; Native includes Linux, Windows, iOS and macOS. Setup instructions cover Gradle, Maven and Kotlin Multiplatform projects. Integrations include Spring, Koin, Ktor, Allure, Testcontainers, WireMock and Micronaut. An IntelliJ plugin provides test run icons, editor results, a test explorer, structure highlighting and breadcrumbs. Kotest is free, with a free plan and no free trial. Its assertions library can also be used with JUnit, Spock or another test framework.

Pest is a free PHP testing framework for developers and AI agents, installed in a PHP project as a Composer development dependency. Pest 5 requires PHP 8.4 or later. It supports parallel execution, coverage, mutation and snapshot testing, profiling, architectural testing and browser testing. Its Browser plugin uses Playwright for page interactions, while the Agent plugin lets coding agents run one-off application checks and can drive a real browser when the Browser plugin is installed. Pest Evals combines deterministic tests with AI-powered scorers for evaluating LLM output. The Tia Engine reruns tests affected by recent changes and requires PCOV or Xdebug as a coverage driver. Pest 5 includes PHPStan and Rector plugins; team-maintained plugins include Faker, Laravel and Livewire. JetBrains maintains the PhpStorm plugin, included by default since version 2023.3. Pest supports parameterized cases but does not include built-in mocks. Its maintainers say bug fixes for outdated major versions are available for 12 months after the latest version's release, without a guaranteed resolution time or fix for every issue.