1# llimphi-test
2
3Headless, deterministic golden-image harness.
4
5The problem it closes: in `PLAN-NUCLEO-RETENIDO.md` and `PARIDAD-FLUTTER.md`
6every block used to end with "still to verify on metal / PNG diff pending", and
7CLAUDE.md §8 forbids routine render-and-look because of its token cost. This
8crate turns that expensive, subjective verification into `assert_golden!(...)`:
9cheap, objective, in CI, certified by **text** (`DiffStats`).
10
11## Determinism
12
13The `Harness` asks for a `Hal` through the **software** adapter
14(`llimphi_hal::Hal::new_headless(true)`): the llvmpipe/lavapipe rasterizer
15(deviceType CPU) produces the **same pixel** on any host and in CI, not tied to
16the GPU of whoever generated the golden. If the machine has no fallback adapter
17it falls back to the normal one, and `GoldenConfig`'s perceptual tolerance
18absorbs the vendor difference.
19
20## Typical use (inside another crate's test)
21
22```ignore
23use llimphi_test::assert_golden;
24#[test]
25fn card_with_shadow() {
26    let v = my_widget::card(...);
27    assert_golden!("card_with_shadow", v, 400, 240); // tests/goldens/card_with_shadow.png
28}
29```
30
31Regenerate the goldens with `LLIMPHI_GOLDEN_UPDATE=1 cargo test`.
32
33---
34
35Part of **llimphi** — see [llimphi](../README.md).