Test Automation
GrowthBook is an open-source feature flagging and A/B testing platform. Its JavaScript SDK is designed to be testable: it accepts forced variations and feature overrides, making unit and integration tests straightforward. SDK Setup npm install @growthbook/growthbook # React npm install @growthbook/growthbook-react Copy Basic Usage // lib/growthbook.js import
Test Automation
MailHog is a self-hosted fake SMTP server written in Go. It captures all outgoing emails and exposes them via a web UI and REST API. It runs as a single binary or Docker container with no configuration required. Installation # Docker (recommended) docker run -d -p 1025:1025 -p 8025:8025
Test Automation
Image processing is a common source of production bugs: wrong dimensions, incorrect formats, quality degradation, metadata exposure (EXIF with GPS coordinates), and broken pipelines. Testing it requires generating test images programmatically and asserting on processed output. Generating Test Images with Sharp Don't commit test images to version control.
Test Automation
File upload testing covers the entire pipeline: browser-to-server transfer, server-side validation, storage, and post-processing. Each stage needs different testing strategies. Testing the Upload Endpoint Node.js with Multer // routes/upload.js import multer from 'multer' import path from 'path' const upload = multer({ limits: { fileSize: 5 * 1024
Test Automation
Writing the email and ensuring it sends is only half the job. The other half is ensuring it actually reaches the inbox. Email deliverability testing validates that your DNS configuration, email headers, and content won't cause your emails to be rejected or filtered as spam. What Affects Deliverability
Test Automation
Feature flags introduce conditional logic that multiplies the number of code paths your application can take. Without a deliberate testing strategy, you end up with tests that only cover one flag state, silent regressions when flags change, and untested code accumulating behind flags. The Core Problem A single feature flag
Test Automation
BullMQ is the most popular Node.js queue library. It's built on Redis and supports job retries, priorities, rate limiting, and repeatable jobs. Testing BullMQ requires understanding its architecture: queues add jobs, workers process them, and both communicate through Redis. Architecture for Testability Structure your code to separate
Test Automation
Celery is the standard distributed task queue for Python. Testing Celery tasks requires deciding whether to run them synchronously (unit tests) or asynchronously against a real broker (integration tests). Task Structure for Testability Separate task logic from the Celery decorator: # tasks/email_tasks.py from celery import shared_task from
Test Automation
Several tools exist for intercepting and testing emails during development. They all solve the same core problem — capturing outgoing SMTP traffic without delivering it — but differ in features, maintenance status, and hosting model. The Candidates Tool Type Language Last Release License Mailpit Self-hosted Go Active (2024) MIT MailHog Self-hosted Go
Test Automation
Email testing is one of the most overlooked areas of application quality. Sending real emails during tests is slow, unreliable, and leaks data. The solution is a fake SMTP server that captures outgoing messages so you can assert on them without touching a real inbox. The Core Problem Applications send
Test Automation
Background jobs power the asynchronous side of your application: sending emails, processing uploads, syncing data, sending webhooks. Testing them requires different strategies than testing HTTP handlers — you need to control job scheduling, execution, retries, and failure handling. Testing Levels Unit tests: Test the job's processing logic in isolation.
Test Automation
Audio applications span podcasts, voice messages, music processing, and real-time communication. Testing audio is harder than images because you can't easily "see" the output — you need to assert on metadata, waveform properties, or transcriptions. Testing Audio Format Conversion // services/audio-processor.js import { execFile } from 'child_