author Eitan Isaacson <>
Thu, 20 Dec 2018 16:03:00 -0500
changeset 501491 c58ea2229c337e9981ab9d3650b04fd3d249b141
parent 458409 a4dc7628629924b778c6409743836b539017cd86
permissions -rw-r--r--
Bug 1513912 - Null check return from TextToSpeech.getFeatures(). r=agi, a=jcristau

# wrench

`wrench` is a tool for debugging webrender outside of a browser engine.

## headless

`wrench` has an optional headless mode for use in continuous integration. To run in headless mode, instead of using `cargo run -- args`, use `./ args`.

## `replay` and `show`

Binary recordings can be generated by webrender and replayed with `wrench replay`. Enable binary recording in `RendererOptions`.

RendererOptions {
    recorder: Some(Box::new(BinaryRecorder::new("wr-frame.bin"))),

If you are working on gecko integration you can enable recording in `webrender_bindings/src/` by setting

static ENABLE_RECORDING: bool = true;

`wrench replay --save yaml` will convert the recording into frames described in yaml. Frames can then be replayed with `wrench show`.

## `reftest`

Wrench also has a reftest system for catching regressions.
* To run all reftests, run `script/ reftest`
* To run specific reftests, run `script/ reftest path/to/test/or/dir`
* To examine test failures, use the [reftest analyzer](
* To add a new reftest, create an example frame and a reference frame in `reftests/` and then add an entry to `reftests/reftest.list`