msglist: Leave blank space for "mark as read" button so using it doesn't cause messages to shift

[gnprice]

A request from @terpimost. See chat thread.

This is a sort of followup to #400.

[abelaba]

Hello,

I have been going over the codebase for a couple of days now to understand the project more and read about Zulips best git practices. I would love the chance to work on this project and work on this issue.

I have been able to locate which file I need to work on to fix this issue and I have started working on it.

[abelaba]

I have been able to fix this issue by updating the MarkAsReadWidget. Currently, I am trying to find a way to update the existing tests. The tests were previously written to check if the size of the widget > 0, but that won't work anymore since the widget will always have a size.

[gnprice]

Hi @abelaba, welcome. I've assigned you the issue.

For questions about details of the code, the best place would be a chat thread in #mobile-team on chat.zulip.org.

In general, one thing we try to do when writing tests is to write them in a way that reflects the UI as the user sees it. So: as far as the user is concerned, what's different when the button is shown vs. when it's not shown? After your changes, the size of that widget will be the same in both cases; but there will be other things that are different. So then try to write a test that checks for one of those differences.

If you have follow-up questions after spending some time trying to do that, please go ahead and start a thread in #mobile-team with details on what you've thought or tried so far, and we'll be glad to help.