Probar
Probar (Spanish: "to test/prove") is a Rust-native testing framework for WASM games, providing a pure Rust alternative to Playwright/Puppeteer.
Installation
Probar is distributed as two crates:
| Crate | Purpose | Install |
|---|---|---|
| jugar-probar | Library for writing tests | cargo add jugar-probar --dev |
| probador | CLI tool for running tests | cargo install probador |
Library (jugar-probar)
Add to your Cargo.toml:
[dev-dependencies]
jugar-probar = "0.3"
#![allow(unused)] fn main() { use jugar_probar::prelude::*; }
CLI (probador)
cargo install probador
# Validate a playbook state machine
probador playbook login.yaml --validate
# Run with mutation testing
probador playbook login.yaml --mutate
# Export state diagram
probador playbook login.yaml --export svg -o diagram.svg
# Start dev server for WASM
probador serve --port 8080
Features
- Browser Automation: Chrome DevTools Protocol (CDP) via chromiumoxide
- WASM Runtime Testing: Logic-only testing via wasmtime (no browser overhead)
- Visual Regression: Image comparison for UI stability
- Accessibility Auditing: WCAG compliance checking
- Deterministic Replay: Record and replay game sessions
- Monte Carlo Fuzzing: Random input generation with invariant checking
- Type-Safe Selectors: Compile-time checked entity/component queries
- GUI Coverage: Provable UI element and interaction coverage
Feature Flags
| Feature | Description |
|---|---|
browser | CDP browser automation (chromiumoxide, tokio) |
runtime | WASM runtime testing (wasmtime) |
derive | Type-safe derive macros (probar-derive) |
Why Probar?
| Aspect | Playwright | Probar |
|---|---|---|
| Language | TypeScript | Pure Rust |
| Browser | Required (Chromium) | Optional |
| Game State | Black box (DOM only) | Direct API access |
| CI Setup | Node.js + browser | Just cargo test |
| Zero JS | Violates constraint | Pure Rust |
Design Principles
Probar is built on pragmatic testing principles:
- Poka-Yoke (Mistake-Proofing): Type-safe selectors prevent runtime errors
- Muda (Waste Elimination): Zero-copy memory views for efficiency
- Jidoka (Autonomation): Fail-fast with configurable error handling
- Genchi Genbutsu (Go and See): Abstract drivers allow swapping implementations
- Heijunka (Level Loading): Superblock scheduling for consistent performance