The problem
Every developer knows this pain:
- Clone a repo
- Want to run the tests
- Open the README
- Scroll... scroll... find a "Development" section... maybe
- Figure out it's
pnpm test(notnpm test, notyarn test) - Run it wrong anyway because you needed
pnpm installfirst
Multiply this by every repo you touch. Every PR you review. Every onboarding.
I got tired of it.
The solution: rex
git clone https://github.com/some/repo
cd repo
rex test
That's it. Rex looks at your project files, detects the stack, and runs the correct command. No config. No setup. No reading anything.
How it works
Rex reads files in your project root:
| File found | Stack detected | rex test runs |
|---|---|---|
go.mod | Go | go test ./... |
package.json + pnpm-lock.yaml | Node + pnpm | pnpm test |
Cargo.toml | Rust | cargo test |
pyproject.toml + uv.lock | Python + uv | uv run pytest |
composer.json + artisan | PHP + Laravel | php artisan test |
Gemfile + app/ | Ruby + Rails | bundle exec rails test |
pom.xml | Java + Maven | mvn test |
build.gradle | Java + Gradle | ./gradlew test |
build.zig | Zig | zig build test |
mix.exs | Elixir | mix test |
Makefile | Make | make test |
Justfile | Just | just test |
12 ecosystems. It also detects which package manager you use by looking at lockfiles.
Demo
Or grab a binary from If this solves a pain you've felt, star the repo. If you want a stack added, open an issue.
Install
# Homebrew (macOS/Linux)
brew tap rexrun-dev/tap && brew install rex
# Go
go install rexrun.dev/rex/cmd/rex@latest
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