1. Your contributing guidelines mention I should skip writing tests for endpoints that don't support app auth. According to the docs, that's all of the workbook endpoints. Is there any way I can write tests we can use for these endpoints?

Not really. You can test them locally. We are working on test recording to allow us to record delegated-auth tests and replay them to validate.

2. In my testing, I wasn't able to use workbook operations on items opened by path. These failed with "Could not obtain a WAC token". When I use getItemById, it works. I wrote this off as a Graph API bug, but haven't tested extensively.

Don't know, WAC is the office protocol, perhaps that endpoint requires something special.

3. My current implementation of workbook sessions involves a workbook property on DriveItem that leads to a regular, sessionless IWorkbook and an async method getWorkbookSession that resolves to an IWorkbookWithSession. The latter is an extension of IWorkbook that adds session refresh/close methods, and uses the InjectHeaders behaviour to add the session id header. Thoughts on this approach?

I am not deeply familiar with this API, what is the difference between sessionless and with session? Do we need to expose both?

4. I've added a prefer-async behavior to the graph folder. This is to handle the long-running operation pattern that a few of the workbook endpoints support. Again, I'm not sure if this is the ideal approach, but it's what I've got at the moment.

This is pretty slick, I left a few notes inline. This isn't something we built-in for v4 launch, but I can see a ton of value to including it.

Again, nice work!

HI @ChapC is this ready? We see your changes, we were just waiting on anymore feedback from you.

Hey @bcameron1231, I've just added a few more of the endpoints I've tested recently. I was hoping to cover much more of the workbook functionality, but I've ended up with much less time than I thought I would have on this. Apologies!

So far, of all the workbook sections, I've implemented the basic stuff in Tables, Worksheets, Rows/Columns and Ranges. Everything to get/update/delete data in the spreadsheet. I have mocha tests for most of these on my local machine, although they're in a separate project as I had trouble getting it working with this one.

There were a couple quirks I encountered in these endpoints. Most I mentioned previously, but the biggest one I couldn't find a fix for was incompatibility with paging. The async iterator doesn't work for table rows, because as far as I can tell the Graph API simply doesn't return hasNext, count, etc. for the workbook/{table name|id}/rows endpoint. I've replicated this in Graph explorer as well. You can add top and skip, just fine, but count has no effect and the responses never include @odata.nextLink.

There's still quite a bit more for full coverage of all endpoints, like charts, running formulas and cell styling. I'm happy to keep chipping away at these features, just won't have a timeframe for you unfortunately. I can get some documentation written up soon if you guys decide you'd like to merge just the stuff I've got working rather than the full set. Just let me know :)

Also, to answer the question from @patrick-rodgers regarding session vs sessionless; my understanding is that both work for pretty much every endpoint, but using a session leads to better performance. It's briefly explained in the docs here. To quote them directly:

The session header is not required for an Excel API to work. However, we recommend that you use the session header to improve performance.

It also allows you to create non-persistent sessions, in which you can edit the workbook and run calculations without your changes being saved to the file. In sessionless mode, your changes are always immediately saved to the file.

Sounds good @ChapC! No worries, we're all busy so appreciate any time you have to contribute 😀 Let us know once you're ready for a full review. Thank you!!