ENH: Added button parsing in eyelink _utils.py

[WouterKroot]

Reference issue (if any)

What does this implement/fix?

Additional information

[welcome]

Hello! 👋 Thanks for opening your first pull request here! ❤️ We will try to get back to you soon. 🚴

[scott-huberty]

@larsoner do you think it is worth adding a tiny ASCII test file with a button press event in it, to https://github.com/mne-tools/mne-testing-data ?

@WouterKroot , if Eric says yes - would you be willing to provide such a tiny test file? (can be 1-second of data similar to this one

[larsoner]

Or even better than adding a whole new file, take an existing file, copy to temp dir in a test while modifying it to add a button line / lines, then use that. That way we don't need to update our test dataset for a single new data line

[scott-huberty]

Or even better than adding a whole new file, take an existing file, copy to temp dir in a test while modifying it to add a button line / lines, then use that. That way we don't need to update our test dataset for a single new data line

@WouterKroot we have a function in the EyeLink test suite that does a bit of @larsoner describes, here, Is this something that you can try to add simulated BUTTON events to?

Admittedly, the logic of the linked function is a little hairy since it requires a good understanding of EyeLinks ASCII file specification.. So let me know if you need help. I'm unfortunately running low on availability these days, but happy to help as much as I am able to.

[WouterKroot]

Sure,I will take a look at it. In any case I do have Eyelink files with Button events in it, so I could just copy such an event and add it to a temporary file for testing.

I’ll let you know if I need some help, thanks!