Having a reference implementation and a test suite are to themselves good things. I don't know that they necessarily belong together, though.

The test suite should be something that an implementor can use to verify their implementation. They don't need the reference implementation to do that.

The JSON Schema Test Suite is a good pattern to follow. It only outlines the tests in a deserializable format that gives some test data and the expected result.

This file from the JSON Path Comparison site code is probably the best place to start for getting test cases. I've implemented this as an interim suite, using those cases that have consensus as the desired outcome (save for a few exceptions). Though I think serializing it with JSON might make things easier (since we're defining a JSON mechanism and we should already have tooling to deal with it versus YAML).