SyncUp tutorial fixes

[dafurman]

Here's a PR fixing a variety of issues I found while going through the tutorial. Overall it was quite good though!

[dafurman]

To ensure that there's always an attendee, so that

var durationPerAttendee: Duration {
    duration / attendees.count
}

doesn't crash

[dafurman]

I found that the testRemoveAttendee() function fails, rather than passes as the instructions state.
The pathway to fixing this pretty much comes down to a lot of the same logic in testRemoveFocusedAttendee, so in this PR I suggest just dropping testRemoveAttendee() in this tutorial and only focusing on testRemoveFocusedAttendee().

[dafurman]

I ended up reverting changes here, to make this PR easier to review.
If you'd like, I can do a followup PR to make the changes I've mentioned here, once this PR is merged, or if you want to handle it in your own way that's cool too.

[dafurman]

To avoid conflicting with the SwiftUI.App protocol, I switched mention of this to AppFeature. There were a couple times where this was referenced as AppFeature in the tutorial anyways, so it seemed like the right name.

[dafurman]

Necessary for compilation, and I added a note on this in the tutorial where this gets added.

[dafurman]

Figured I'd toss this small blurb in here too, but it can be removed if you want.

[dafurman]

Applies the most basic override before we give it something better in the next step, per

Override the dismiss dependency in the withDependencies trailer closure.

[stephencelis]

Just curious was there actually a dismiss-related test failure in your runthrough? There used to be, but these days the test store automatically tears down effects when dismiss() is called by the reducer.

[dafurman]

Changes regarding these files add one more step and some tutorial commentary to go from

extension URL {
  static let syncUps = Self.documentsDirectory.appending(component: "sync-ups.json")
}

to

extension PersistenceReaderKey
where Self == PersistenceKeyDefault<FileStorageKey<IdentifiedArrayOf<SyncUp>>> {
  static var syncUps: Self {
    PersistenceKeyDefault(
      .fileStorage(.documentsDirectory.appending(component: "sync-ups.json")),
      []
    )
  }
}

In the current version of the tutorial, later on, this shorthand version is used, so we might as well just standardize on this throughout the tutorial, and this ensures that later parts of the tutorial compile.

[mbrandonw]

Hi @dafurman, thank you very much for taking the time to make these fixes to our tutorial! It is incredibly kind of you and we are very appreciative.

It is going to be a bit tough for us to make the time to review this PR, as is. Many of the changes are no-brainers, and we would happily pull them in, but others require us to actually go through the tutorial and make sure that it works as intended.

If you have a bit more time, you could separate out the simple changes from the complex ones in a separate PR, and that would allow us to merge the simple changes quickly, and make it easier for us to vet the complex ones later.

I think the simple ones include:

• Simple typos
• Poorly formatted code like the {@MainActor stuff in tests
• Obviously missing code like durationPerAttendee
• And you can delete the commented out code

And if there is anything else you think is "simple" then please do include that.

If you were to PR those things we could happily merge, and then that might help make this PR a little smaller for us to grok.

[dafurman]

If you have a bit more time, you could separate out the simple changes from the complex ones in a separate PR, and that would allow us to merge the simple changes quickly, and make it easier for us to vet the complex ones later.

If you were to PR those things we could happily merge, and then that might help make this PR a little smaller for us to grok.

Sure that's completely understandable, I was a bit worried about the PR size myself.

I'll break this out into sensible chunks of complexity as you've suggested sometime this week!

[mbrandonw]

Hi @dafurman, we merged a bunch of tutorial fixes today and so you should be able to merge main into your branch to see what is left. Hopefully it isn't too much of a pain.

[dafurman]

@mbrandonw Alright, this should be ready for review now and be easier to look at this time around!

[stephencelis]

This is great! I went through everything and they're all great improvements.

I pushed a few small things and am gonna merge as-is, but if you have a project in a handy state, I had a question.

[stephencelis]

Just curious was there actually a dismiss-related test failure in your runthrough? There used to be, but these days the test store automatically tears down effects when dismiss() is called by the reducer.

[dafurman]

@stephencelis

#3139 (comment)

Just curious was there actually a dismiss-related test failure in your runthrough? There used to be, but these days the test store automatically tears down effects when dismiss() is called by the reducer.

Sorry bout the delay - been busy lately.
I think you're right though, because if I take the version of the test at step ImplementingTimer-04-code-0012.swift, I just get these 2 errors, instead of the 4 mentioned:

And then following the next step fixes that test, so this part of the tutorial could probably be shortened!