Rust-Only Runtime
Runs inside a single Rust process. No external browser, WebDriver, or Node.js dependency.
Open Source / Crate
browser-tester
browser-tester is a deterministic browser-like test runtime implemented in pure Rust. It validates DOM and event behavior without launching a real browser.
Rust
Deterministic Runtime
DOM Testing
What This Crate Is Good At
browser-tester focuses on predictable form/UI behavior tests rather than full browser rendering compatibility.
Deterministic Execution
Built for repeatable tests by design: fake clock, deterministic random seed, and explicit timer control APIs.
DOM + Event Testing
Supports practical browser-like flows: selectors, inline script execution, event propagation, and DOM updates.
Fast Local Feedback
Fast feedback cycle for form-centric UI tests, while keeping failure output focused on selectors and expected/actual values.
Quick Start
Create a harness from HTML, run interactions, and assert DOM results. Start with a small fixture and expand with timer/mock APIs.
Install
cargo add browser_tester
Basic Example
Main API Surface
Harness Actions + Assertions
Core DOM test operations: Harness::from_html, type_text, set_checked, click, submit, and assertion helpers for text/value/checked/existence.
Deterministic Timers
Control asynchronous behavior with a fake clock. Advance time deterministically using advance_time, advance_time_to, flush, and timer inspection APIs.
Built-in Mocks
Inject fetch responses and dialog outcomes with set_fetch_mock, enqueue_confirm_response, and enqueue_prompt_response to keep tests isolated.
Trace & Diagnostics
Enable trace logs and extract event/timer flow when a test fails. Useful for debugging event order and default action behavior.
Runtime Policy
- eval is intentionally unsupported to preserve security and determinism.
- This runtime targets practical test scenarios, not 100% real-browser compatibility.
- External network I/O is out of scope; use fetch mocks for test coverage.
If you need additional browser APIs for your test suite, open an issue with a minimal fixture to discuss scope and priority.