Add documentation about new test explorer implementation

[vinistock]

With the new test explorer implemented, there are two pieces of documentation we have to update:

User documentation

We should add a new markdown page dedicated to user documentation about the explorer, explaining all of the limitations and features that we provide. Things like:

• The modes of execution (run, run in terminal, debug, coverage)
• Continuous mode support
• The environment variable we provide for customization when running tests through the explorer
• Keybindings
• The fact that tests are discovered through static analysis and meta-programmed tests will either not be available or will only be discovered after the first run

Add-on documentation

We need to document how add-ons can contribute to test discovery and execution through the new APIs, with a simple example of how to do it.

[domingo2000]

Last week i tried to implement this new Test Discovery Items based on the PRs of your own implementations for the Minitest::Spec in this addon for the minitest shoulda context dsl. But i saw the test explorer was still under a feature flag in the lsp IDE settings.

¿Are you planning an official date, documentation or release when i could implement that migration from the old code lens aproach?. I will watch this issue for now.

Also willing to do the implementation on my side and after that document a simple implementation in the addon docs in this repository based on the experience gained.

[vinistock]

We're still fixing a few issues we discovered before the rollout, but I expect we'll be starting with a small percentage some time this week or the next. I can ping this issue when we start rolling it out.

Concerning the add-on API, it has roughly three pieces:

• Test discovery Add test discovery support for ActiveSupport declarative syntax ruby-lsp-rails#591
• Test command resolution Add Rails test command resolution ruby-lsp-rails#596
• Code lens contribution Push test code lens to response builder on test discovery ruby-lsp-rails#605

If you have feedback about the APIs (or eventually the docs), please do let us know here! I should have something written for the docs soonish.

[vinistock]

@domingo2000 I just put up #3488, which documents the test discovery portion of the API. Let us know if you have any feedback! We want to make it as clear as possible.

[domingo2000]

I've added a comment to the documentation.

I've started a draft implementation for test discovery and noted some blockers encountered during development. The discovery phase was successful, populating the TestItem objects works fine. However, I encountered issues with the test command resolution step.

The main issue is that requests aren't triggered for inner groups within test classes. This problem also affects minitest/spec DSL examples (that implementation is similar to my addon) when describe syntax is under a class or have inner describe blocks. To address these integration problems with the new test explorer and both minitest/spec and my addon, ¿Should i open open a new issue or pull request to adress those problems?.