CardboardTest

A small compatibility probe for Cardboard.

It covers the two areas that headless testing cannot reach:

• NMS reflection — CraftPlayer#getHandle, ServerPlayer#connection by field reflection, CraftServer#getServer, Class.forName on unobfuscated NMS names, and CraftWorld#getHandle.
• Custom inventories — creating a GUI, item display names and lore, the metadata round trip, and InventoryClickEvent / InventoryCloseEvent (including closing from inside the click handler).

Every probe is caught and reported individually as [PASS] / [FAIL], so a partial failure still tells you which surface broke.

Usage

/cbtest all     # everything
/cbtest nms     # NMS reflection only
/cbtest meta    # item metadata only
/cbtest gui     # open the inventory probe

Building

./gradlew jar     # -> out/CardboardTest.jar

Requires JDK 25 (auto-provisioned) because paper-api 26.2 targets Java 25.

Result on Cardboard 26.2

All probes pass. See the Cardboard 26.2 release.