Testing
Remix organizes your app around routes, loaders, and actions. Loaders fetch data before the route renders. Actions handle form submissions. Route components display the data. This structure makes testing straightforward — each piece has clear inputs and outputs you can verify independently. This guide covers the full Remix testing stack: Vitest
Testing
Remix and Next.js are both full-stack React frameworks, but their approaches to server-side code differ in ways that significantly affect how you write tests. This guide compares the testing experience of both frameworks — what's easier, what's harder, and what patterns carry over between them. Data
Testing
Forms in Remix work differently from most React frameworks. Remix forms submit to server actions, which return structured data or throw redirects. Testing this pattern requires understanding both sides: the action logic and the component that displays action errors. This guide covers everything you need to test Remix forms thoroughly:
Testing
Remix loaders and actions are the backend of your application. Loaders fetch data; actions handle mutations. Both are pure functions that take a request and return a response — which makes them easy to test without a running server. This guide goes deep on testing Remix loaders and actions: constructing requests,
Testing
Deno Fresh is a full-stack framework built on Deno, Preact, and server-side rendering. It follows a "no build step" philosophy — components render on the server by default, and interactive parts (called Islands) hydrate on the client. Testing Fresh apps covers three areas: 1. Route handlers — the server functions
Testing
Remix's file-based routing, nested routes, and server-side rendering require E2E tests that exercise the full stack. Playwright is the right tool: it runs tests in real browsers, handles JavaScript-rendered content, and integrates cleanly with Remix's dev server. This guide covers Playwright setup for Remix, writing tests
Testing
SvelteKit ships without a testing setup. You create a project with npm create svelte@latest, pick a template, and get a working app — but zero tests. This guide covers everything you need: unit tests for utilities, component tests for Svelte components, integration tests for load functions and API routes, and
Testing
Playwright is the E2E test runner of choice for SvelteKit. It drives a real browser — Chromium, Firefox, or WebKit — against your running app. Unlike Vitest component tests that run in jsdom, Playwright tests exercise real browser behavior: navigation, cookies, local storage, JavaScript rendering, and network requests. This guide covers Playwright
Database Testing
Prisma has become one of the most popular ORMs in the Node.js ecosystem, and for good reason. Its auto-generated TypeScript client, powerful migration system, and intuitive query API make database work genuinely pleasant. But testing Prisma-based applications requires a clear strategy — one that separates fast unit tests from thorough
Testing
SvelteKit API routes (+server.ts) and server load functions (+page.server.ts) contain your application's backend logic. They handle request validation, database queries, authentication checks, and error responses. Testing them directly — without starting a server — is fast, reliable, and catches the class of bugs that frontend tests completely
Testing
SvelteKit form actions handle POST requests from <form> elements on the server. They validate input, interact with databases, send emails, and return structured responses. Testing them directly — without a running server — catches validation bugs, missing error handling, and incorrect redirects before they reach users. How Form Actions Work
Testing
Svelte stores hold application state. When store logic is wrong — a derived value computes incorrectly, a custom store doesn't clean up subscriptions, an async store gets stuck in a loading state — components using that store will fail in ways that are hard to trace. Testing stores in isolation