VoxelCore combines focused unit/regression tests with real plugin-capable server smoke tests.

Current tests cover, among other behaviour:

- item compilation and multi-level inheritance;

- missing parents, cycles, duplicate IDs and required-field validation;

- deep immutability of compiled definition data;

- YAML loading/discovery and strict schema handling;

- stable render allocation and tombstone behaviour;

- structured semantic-key typed indices and type-change rejection;

- runtime reload rollback and successful publication;

- `ItemManager` use of the active snapshot allocation;

- platform version parsing, including Paper's build-qualified 26.2 version;

- item metadata flag resolution;

- deterministic Java pack output and modern rule generation;

- 26.2 `min_format`/`max_format` pack metadata;

- config migration preserving operator values;

- unbound definitions being excluded from `item list`.

Validated exact servers:

1. 1.12.2

2. 1.13.2

3. 1.14.4

4. 1.19.4

5. 1.20.5

6. 1.21.4

7. 26.2

The smoke path goes beyond “plugin enabled”: it waits for the `VOXELCORE_READY` marker, exercises content/admin behaviour, verifies create → stored ContentID → identify round trips, validates/builds the exact resource-pack target, deliberately triggers a failed reload and confirms the old revision remains active, then restores valid content and confirms a successful new revision.

The repository currently carries `mvp-content`, `mvp-content-legacy` and `mvp-content-modern` fixtures so rendering boundaries can be exercised without pretending one authored render representation behaves identically on every client generation.