Development Setup

Prerequisites

cargo-nextest

We use cargo-nextest instead of cargo test. It runs each test in its own process, which lets us install a process-wide tracing subscriber without conflicts.

bash

cargo install cargo-nextest

cargo-insta

We use insta for snapshot testing. When a snapshot changes, review it with:

bash

cargo insta review

just

just is a task runner. The justfile defines common workflows.

bash

# macOS
brew install just

# or with cargo
cargo install just

Quick start

bash

git clone https://github.com/facet-rs/facet
cd facet
just ci

just ci runs locally what CI runs remotely. If it passes, your PR will likely pass CI.

Common commands

bash

# Run all tests
cargo nextest run

# Run tests for a specific crate
cargo nextest run -p facet-json

# With tracing output
RUST_LOG=debug cargo nextest run -p facet-reflect

# Review snapshot changes
cargo insta review

# Check for undefined behavior
just miri

# Check no_std compatibility
just nostd