Testing
PyTorch models fail silently — a wrong tensor shape produces garbage outputs without errors. pytest-based unit tests catch shape mismatches, gradient issues, and training bugs early. This guide covers practical patterns for testing PyTorch models at every level. Why PyTorch Models Need Unit Tests Deep learning bugs are subtle: * Shape mismatches
Testing
Catch2 is the modern C++ testing framework that prioritizes natural expression over boilerplate. Its SECTION model eliminates test fixture overhead, expression decomposition shows you actual values on failure without custom assertion messages, and BDD-style macros make test intent self-documenting. Catch2 vs Google Test: When to Choose Which Both are excellent.
Test Automation
Playwright supports browser extension testing in Chromium (full support) and Firefox (experimental). Use chromium.launchPersistentContext() with --load-extension and --disable-extensions-except flags. For Firefox, launch with firefox.launchPersistentContext() and set firefox_profile preferences. Access the extension popup by navigating directly to its chrome-extension:// URL. Key Takeaways Use launchPersistentContext, not browser.newPage. Extensions
Testing
LocalStack runs a local mock of AWS services in Docker. Instead of mocking the AWS SDK in your tests, point the SDK at LocalStack's endpoint and test against a real (local) S3, DynamoDB, SQS, or Lambda. This catches integration bugs that SDK mocks miss: serialization issues, IAM permission
Database Testing
SQLite's in-memory mode — :memory: — creates a complete, full-featured SQL database that lives entirely in RAM and disappears when the connection closes. It's been the secret weapon for fast unit tests in every major web framework for over a decade. This guide covers how to set it
Database Testing
Redis powers some of the fastest parts of modern applications — caches, session stores, queues, leaderboards. But testing Redis-backed code is often skipped or done poorly, leading to bugs that only show up in production. This guide covers unit testing with fakes, integration testing with real Redis, and patterns that actually
Database Testing
PostgreSQL is the world's most popular open-source relational database — and testing PostgreSQL-backed applications is one of the most important skills a backend engineer can have. This guide covers the full spectrum: fast in-memory tests with pg-mem, realistic integration tests with Testcontainers, and patterns that scale to production complexity.
Database Testing
MongoDB's document model is flexible and developer-friendly — but that flexibility makes testing tricky. Schema validation is optional, embedded documents nest arbitrarily deep, and aggregation pipelines can be complex. This guide covers every layer of MongoDB testing, from fast in-memory fakes to real container-based integration tests. Testing Approaches for
Database Testing
DynamoDB is fast and serverless in production — but testing against live AWS DynamoDB is expensive, slow, and requires real AWS credentials. DynamoDB Local, LocalStack, and AWS SDK mocking solve this, letting you run fast, reliable tests without touching AWS. This guide covers all three approaches across Python and Node.js.
Fuzz Testing
AFL++ (American Fuzzy Lop Plus Plus) is the most widely used coverage-guided fuzzer in the world. It has discovered thousands of vulnerabilities in production software — from image parsers to network protocols to cryptographic libraries. This tutorial walks you through setting up AFL++, instrumenting a target, building an effective corpus, and
Game Testing
Unreal Engine ships with a built-in Automation Testing Framework that supports unit tests, functional tests, and performance testing at scale. Unlike Unity's external testing ecosystem, Unreal's automation is deeply integrated with the engine and supports testing both C++ game logic and Blueprint assets. Unreal Automation Testing
Game Testing
Game testing in Unity isn't just clicking through levels — it's a discipline with proper unit tests, integration tests, and automated CI pipelines. The Unity Test Framework (UTF) gives you a test runner inside the Unity Editor that integrates with standard test tooling. The Unity Test Framework