unity-testability

To improve Unity testability, you move core gameplay logic out of MonoBehaviour into plain C# classes and write unit tests for the new classes. This isolates logic from scene state to enable reliable EditMode testing.

The best way to test MonoBehaviour classes is to refactor them by moving heavy logic into pure C# classes, allowing you to mock dependencies and write reliable unit tests without relying on Unity scene state.

You need EditMode testing to run fast unit tests on isolated pure C# logic, while PlayMode testing is used to verify Unity integration points and behaviors that depend on scene state and MonoBehaviour lifecycle.

You mock Unity APIs by extracting logic into pure C# classes and using dependency injection to introduce mockable interfaces. This allows tests to bypass Unity integration points and verify logic paths directly.

Yes, you can refactor large Unity projects by applying incremental refactoring with minimal risk. This involves gradually moving logic to pure C# classes and maintaining Unity integration through lightweight wrappers.

Relying on MonoBehaviour makes unit testing hard because it couples your logic tightly to Unity scene state and lifecycle methods. Refactoring to pure C# classes isolates the logic, ensuring tests cover new logic paths reliably.