Rocha

Rocha is a blazing-fast native (Rust) orchestrator for Mocha-style test suites, designed as a drop-in replacement for the mocha CLI.

Rocha keeps test execution in standard Node.js workers while shifting file discovery, TypeScript/ESM transforms, process pooling, scheduling, timeouts, and report generation into native compiled code.

Key Highlights

• Drop-in Mocha Parity: Supports .mocharc.* configuration, standard CLI flags, BDD/TDD/QUnit interfaces, and all Mocha reporters (spec, dot, min, list, tap, json, xunit).
• Instant TypeScript Transforms: Built-in native Oxc transformer. Run .ts, .tsx, .mts test files directly without ts-node, tsx, or compilation build steps.
• Warm Worker Pools: Sub-150ms execution on medium test suites (400 files, 5,000 tests) via --isolate=none.
• Timing-Aware Scheduling: Historic run times are tracked and scheduled using an Exponential Moving Average (EMA) to minimize pipeline makespan.
• Orchestrator-Side Hard Timeouts: Process-level timeouts prevent runaway infinite loops from freezing your test runner.
• Smart Watch Mode: AST-based import graph analysis reruns only tests affected by changed files.
• Zero Heavy Dependencies: Lightweight npm wrapper with prebuilt native binaries for Linux, macOS, and Windows.

Quickstart

Run Rocha in any existing Mocha repository using npx:

npx rocha "test/**/*.spec.ts"

Or install locally in your project:

npm install --save-dev rocha
npx rocha --parallel -j 4 "test/**/*.test.js"

Documentation

• Quickstart Guide - Installation and basic usage.
• Migration Guide - Drop-in checklist for migrating from mocha.
• CLI Flag Reference - Complete documentation of all command-line options.
• Isolation Model - Detailed guide to --isolate=none vs --isolate=file.
• Architecture Overview - High-level system topology and crate breakdown.
• Benchmarking Methodology - Performance metrics and replication instructions.
• Cross-Platform Support - Linux, macOS, and Windows compatibility.
• Error UX Guidelines - Exact error messages and diagnostics.
• Real-World Corpus - Evaluation across 10 open-source Mocha repositories.
• Compatibility Ledger - 100% pass rate across conformance fixtures.

Performance Snapshot

| Test Suite | Mocha + ts-node | Rocha (Warm Cache) | Speedup | |---|---|---|---| | medium (400 files, 5,000 tests) | 6.2s | 148 ms | 42x | | large-ts (1,000 files, 10,000 tests) | 38.4s | 2.85s | 13.5x |

License

MIT © Rocha Contributors