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.