Plugin Development Tooling

Two tools save developers the most time once a plugin grows past a single class.

MockBukkit is a mocking framework for Bukkit and Paper. It provides a simulated server so you can write unit tests that create players, run commands and fire events without starting Minecraft. Tests run in seconds and can run on every commit, which catches regressions before they reach a live server.

paperweight is a Gradle build plugin used by Paper and by projects that build on it. Its userdev part lets a plugin compile against the server's internal code, with mapped names, when the public API does not expose what you need. That access is powerful and unsupported by the public API, so it is tied to a specific Minecraft version and breaks more often.

Use mocks for logic that does not depend on real game behaviour, and test the rest on a real server, because a mock is a model of the game, not the game. Keep internals code small and isolated so a version update touches as little as possible.

Can MockBukkit test everything? No. It models the API, not the game itself. Use it for logic and keep a real test server for behaviour.

When should I use internals? When the API does not offer what you need, and accept that you will update that code for each Minecraft version.