Perl support for test runners

[WhoIsSethDaniel]

Probably a pretty big task, but it would be nice if most popular test runners had a decent ability to work with Perl.

I only know Neovim and, being Neovim, it doesn't actually have a "standard" test runner. There are three (but really only two) that I know of:

1. neotest - no runner for perl (but does have a fallback to vim-test)
2. vim-test - has a 'prove' runner. It's not great, but capable. Works with vim as well.
3. vim-ultest - is more of a frontend to vim-test. Works with vim as well. Abandoned b/c the dev now works on neotest

Most test runners that I am familiar with do more than simply run a set of tests. They make it easy to run a single test while editing it. They will constantly run your tests (if you want), or will run your tests on change. Many interpret the output (neotest will do this) and provide colors or clues as to what went wrong. f.e. neotest will tell me line numbers and give context and can also populate the quickfix window with this information. This requires something that parses the output of a test runner.

What editors, besides, Neovim have a test runner (or runners) and adequately support Perl?

What is required to have an experience, comparable to Python or Go, while running and writing tests?

[bmeneg]

That's actually a really good and important support to work on. While reading, debugging comes to my mind too.
Both cases fall into the "scalability" category of a language (Perl in this case, of course): testing and debugging are must for people working on bigger projects. Without proper tools, people tend to debug with the usual prints to log files, but everyone knows how effective a good debugger and efficient dev-test cycles can be.

Your proposal of engaging with such tools (probably except vim-ultest) is completely aligned with this org goal.
Do you have free cycles to work on one of the tools? Or have anyone in mind that would be willing to help?
I'm pretty excited about it and would even join the effort, just need to get rid of some stuff before and try the tools to see how they work on supported languages.

[bmeneg]

@Nihilus118 is it possible to run vscode-perl-debug as an standalone server, eg. in a specific port at localhost?
I did a quick check into the code and find that vscode receives the server address directly.
nvim-dap accepts adapters that are one of the options: executable (cmdline), server (daemon running in the background) and pipe (stdin/stdout).

[WhoIsSethDaniel]

Hi @bmeneg . I was able to get the debugger to work (AFAICT, I got to the point where running continue() didn't bomb out and the UI showed that it had stopped on a breakpoint).

Steps:

1. git clone https://github.com/Nihilus118/vscode-perl-debug
2. npm install typescript
3. npx tsc (this should create a directory named 'out' along with 'node_modules')
4. install nvim-dap as a plugin for neovim
5. nvim-dap configuration:

local dap = require 'dap'
dap.adapters.perl = {
  type = 'executable',
  command = 'node',
  args = { '/path/to/out/debugAdapter.js' }, -- this is in the 'out' directory created in step 4
}
dap.configurations.perl = {
  {
    type = 'perl',
    request = 'launch',
    name = 'Launch Perl',
    program = '${workspaceFolder}/${relativeFile}',
  },
}
dap.set_log_level 'TRACE' 

1. edit a perl file
2. set a breakpoint somewhere (:lua require'dap'.toggle_breakpoint())
3. run the code to breakpoint (:lua require'dap'.continue())

[WhoIsSethDaniel]

The vscode-perl-debug code seems to be able to run as a server, but if you pass no server-related arguments it reads from stdin, writes to stdout. This is pretty typical of these vscode-related plugins.

[WhoIsSethDaniel]

One extra action item from all this is to update the nvim-dap wiki to mention and have sample config for vscode-perl-debug. Right now it only lists a config for Perl::LanguageServer. https://github.com/mfussenegger/nvim-dap/wiki/Debug-Adapter-installation#perl

[bmeneg]

Aha!! Yep, I was missing the debugAdapter.js entry point! Was considering extension.js.
Nicely done, it seems to work just fine! 👏
I'll make a try with nvim-dap-ui now. Seems promising :)
And for sure you should edit nvim-dap's wiki to add yours.

Congrats and thanks for the really nice work.

[WhoIsSethDaniel]

I know there's an outstanding bug with vscode-perl-debug but I've gone ahead and started the process to get this code into mason so that it can be installed easily by neovim users.

mason-org/mason-registry#2563

[WhoIsSethDaniel]

It looks like it was accepted and is now installable via mason.

[WhoIsSethDaniel]

The perl dap adapter (vscode-perl-debug) should be listed here https://microsoft.github.io/debug-adapter-protocol/implementors/adapters/. There is a vscode-perl-debug listed but it is not this one and the one that is listed is dead (see here).

[WhoIsSethDaniel]

I file a bug to list it: Nihilus118/perl-debug-adapter#5

[WhoIsSethDaniel]

I updated the wiki for nvim-dap to include vscode-perl-debug: https://github.com/mfussenegger/nvim-dap/wiki/Debug-Adapter-installation#vscode-perl-debug

[bscan]

For vscode, they have a testing API. I've considered adding support to the Perl Navigator bscan/PerlNavigator#21, although this would only be for vscode users. Although LSP and DAP are standardized protocols for editing and debugging, I don't believe there is a standardized testing protocol across editors.

[Nihilus118]

I am working on a simple prototype right now which is close to being released. But it is only working with Test::Simple so far.
@bscan we could team up working on the test adapter and bundle our extensions using an extension pack.
The test adapter is also able to start a perl debugging session, so it must be bundled with one of the two perl debuggers anyways.

[bscan]

Hi @Nihilus118 , sure I'm happy to collaborate. Let me know when you get a prototype up on GitHub and I can take a look. Thanks!

[Nihilus118]

Hi @bscan, I finally had the time to tidy up some loose ends and release the extension. You can find the code here. I also published the extension on the VSCode Marketplace