1232761571
Summary: Pull Request resolved: https://github.com/facebook/yoga/pull/1813 This adds a unit test to Yoga, which emulates the model of "persistent Yoga nodes" and cloning used by React Fabric, including the private (but relied on) Yoga APIs. It models the over-invalidation exposed in D75287261, which reproduces (due to Yoga incorrectly measuring flex-basis under fit-content, and that constraint changing when sibling changes) but this test for now sets a definite height on A, to show that we only clone what is neccesary, when measure constraints do not have to change. Having a minimal version of Fabric's model in Yoga unit tests should make some of these interesting interactions a bit easier to debug. Changelog: [Internal] Reviewed By: javache Differential Revision: D75572762 fbshipit-source-id: cda8b3fdd6e538a55dd100494518688c864bd233
Yoga 
Yoga is an embeddable and performant flexbox layout engine with bindings for multiple languages.
Building
Yoga's main implementation targets C++ 20 with accompanying build logic in CMake. A wrapper is provided to build the main library and run unit tests.
./unit_tests <Debug|Release>
While not required, this script will use ninja if it is installed for faster builds.
Yoga is additionally part of the vcpkg collection of ports maintained by Microsoft and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.
Adding Tests
Many of Yoga's tests are automatically generated, using HTML fixtures describing node structure. These are rendered in Chrome to generate an expected layout result for the tree. New fixtures can be added to gentest/fixtures.
<div id="my_test" style="width: 100px; height: 100px; align-items: center;">
<div style="width: 50px; height: 50px;"></div>
</div>
To generate new tests from added fixtures:
- Ensure you have yarn classic installed.
- Run
yarn installto install dependencies for the test generator. - Run
yarn gentestin theyogadirectory.
Debugging
Yoga provides a VSCode "launch.json" configuration which allows debugging unit tests. Simply add your breakpoints, and run "Debug C++ Unit tests (lldb)" (or "Debug C++ Unit tests (vsdbg)" on Windows).