Temporal
Temporal activities are where your workflow touches the outside world — HTTP calls, database writes, email sends. Testing workflows in isolation means replacing activities with mocks that return predictable values without making real external calls. Why Mock Activities Activities in Temporal are the "impure" part of the system — they
AWS
AWS Step Functions orchestrate Lambda functions, ECS tasks, and other AWS services into durable workflows. Testing them requires either expensive real AWS calls or local simulation. AWS provides Step Functions Local for exactly this purpose, and moto mocks the underlying AWS services. Testing Approaches Step Functions testing has three levels:
JavaScript
Async JavaScript is everywhere — fetch calls, timers, event handlers, database queries. Testing async code correctly requires understanding how the JavaScript event loop works and how Jest and Vitest provide tools to control it. Async Test Functions Both Jest and Vitest support async/await in test functions natively: // Jest or Vitest
Go
Data races are one of the hardest bugs to find in concurrent programs. Go ships with a built-in race detector that catches them at runtime — no external tools, no setup, just a flag. What Is a Data Race? A data race occurs when two goroutines access the same variable concurrently,
Monorepo
Turborepo is Vercel's high-performance build system for JavaScript and TypeScript monorepos. Its core value for testing is the same as for builds: never do the same work twice. With remote caching, a test that passed on your colleague's machine won't re-run in CI — the
Monorepo
pnpm workspaces provide a lightweight monorepo solution built into the pnpm package manager. Unlike Nx or Turborepo, pnpm workspaces have no build graph awareness or caching — they give you the foundation to run commands across packages, and you layer tooling on top. Understanding how to run tests across packages, share
Monorepo
As a monorepo grows, test code starts to duplicate. Every package writes its own createUser() factory, defines its own API mock handlers, and copies the same Jest setup file. A change to the User type means updating factories in five packages. A new API endpoint means updating mocks scattered across
Monorepo
Nx is one of the most popular monorepo build systems for JavaScript and TypeScript projects. Its key promise for testing is simple: only run tests for code that actually changed. When a monorepo contains dozens of applications and libraries, that promise can cut CI time from 45 minutes to under
Monorepo
Bazel is Google's open-source build system, designed from the ground up for very large monorepos. It powers testing at companies where a single repository contains millions of lines of code across dozens of languages. Its approach to testing is fundamentally different from other tools: Bazel treats tests as
Monorepo
The most common CI problem in monorepos is running too many tests on every commit. A change to a CSS file triggers a full backend test suite. An API schema update re-runs E2E tests for three unrelated apps. Over time, CI becomes a 45-minute wall that developers learn to ignore.
QA Career
QA engineering interviews test both technical knowledge and practical judgment. This guide covers the questions you're most likely to encounter, with answers that go beyond surface-level definitions. Fundamentals 1. What is the difference between testing and debugging? Testing is the process of finding defects — executing software with the
QA Career
The QA engineering career has more defined progression levels than many people realize when they enter the field. Understanding what distinguishes each level helps you set realistic goals and know what to develop next. The Career Ladder Level Typical Years Experience Focus Junior QA Engineer 0–2 years Execution, learning