In-depth tutorials and comparisons for testing tools and frameworks — Playwright, Cypress, Selenium, Robot Framework, and more.
Test Automation
File upload bugs are painful: silent failures, incorrect MIME type handling, size limit bypasses, and S3 permissions that work in dev but fail in production. This guide covers how to test multipart uploads, presigned URL flows, and file download with Jest and Supertest — without hitting real S3. Setup npm install
Test Automation
Celery is Python's most popular distributed task queue. Testing Celery tasks well means covering task logic in isolation, testing how tasks interact with the broker and result backend, and verifying retry behaviour. This guide shows how to do all three with pytest. Setup pip install celery redis pytest
Test Automation
BullMQ is the most widely used Node.js job queue library, built on Redis. Testing it well means covering three separate concerns: the producer that enqueues jobs, the worker that processes them, and the retry/failure handling when things go wrong. This guide shows how to do all three with
Test Automation
Audio applications are hard to test because the output is binary and subjective. Testing speech-to-text accuracy, validating TTS output quality, and verifying podcast processing pipelines all require different strategies. This guide covers practical approaches that give you reliable automated test coverage without requiring audio playback. Testing Speech Recognition Integration Mocking
Test Automation
Background jobs are where most applications hide their most dangerous bugs. A payment job that fires twice, an email job that breaks silently, a report job that fails after 2 hours of work — these failures cost real money and erode user trust. This guide covers the cross-framework testing patterns that
Test Automation
RTK Query is Redux Toolkit's built-in data fetching and caching solution. It generates hooks, reducers, and action creators from endpoint definitions — which means testing it requires a different approach than testing hand-written reducers. You need to test the API layer, cache behavior, and the mutations that invalidate it.
Test Automation
Redux Saga handles side effects (API calls, timers, WebSockets) as generator functions. Testing generators is conceptually simple — call .next() and check what the generator yielded — but in practice there are three distinct approaches to choose from: effect assertion, runSaga integration, and task mocking. Each has its place. Setup npm install
Test Automation
NgRx is the Redux-based state management library for Angular. Testing NgRx requires Angular's TestBed for dependency injection, along with NgRx's own testing utilities: provideMockStore, provideMockActions, and (optionally) jasmine-marbles for observable-based effects testing. Setup npm install @ngrx/store @ngrx/effects @ngrx/store-devtools npm install -D @ngrx/store/
Test Automation
Redux Toolkit (RTK) is the official, opinionated way to write Redux logic. It eliminates the boilerplate of hand-written action creators and reducers, but testing RTK code still requires understanding what to test at each layer: slice reducers, selectors, createAsyncThunk flows, and the store itself. Setup npm install @reduxjs/toolkit react-redux
Test Automation
Effector is a reactive state manager built on the event-sourcing model. Unlike Redux, Effector has no single store — instead, you compose granular units: events, stores, and effects. This makes testing extremely straightforward: each unit is independently testable with no boilerplate. The key testing primitive is fork + allSettled, which gives you
Testing
Module Federation was originally a Webpack 5 feature, but @originjs/vite-plugin-federation brought it to the Vite ecosystem. Testing Vite-based federated modules requires a different setup than Webpack — Vitest is the natural testing tool, and the module resolution strategy for federated imports needs specific configuration. This guide covers setting up Vitest
Testing
Tauri builds desktop applications with a Rust backend and a web frontend (React, Vue, Svelte, or plain HTML/JS). Testing Tauri apps requires a split strategy: Rust unit tests for backend commands, JavaScript/TypeScript tests for the frontend, and integration tests that validate the communication between them. This guide covers