It's been a while since we've seen any significant functional updates from Snapchat, and now, it looks like we might get a couple all at once, with several new features spotted in test mode.
The first one is a new 'Multi-Snap' option in the composer, which would enable users to create a string of Snaps at once, then post them all together.

The option - first spotted by 'Everything Snap' (and shared by Matt Navarra) - would make it easier to compose more planned, structured Snap sequences. There are currently workarounds to do the same - you can compose your Snaps in Aeroplane Mode (so they don't send all at once) or you can save them to your Snap Memories then re-arrange them as you need. But this would make it a simpler process, aligned with the actual functionality within the app, as opposed to having to use workarounds.
Functionally, it's a lot like the option to string together longer videos, which Snapchat released back in 2017.

Keep recording for up to a minute, and the Snap camera will divide your footage into 10-second Snaps, which you can then upload as a Story, effectively enabling longer video Snaps. The new process, is similar, though for still images instead, which adds another element to the composition process.
There's no word on any official launch of the tool, but it makes sense, and would integrate a long-held, unofficial Snap composition system into the app.
The second new function in testing is a new Bitmoji stickers collection for Stories replies.

Spotted by serial social media code hacker Jane Manchun Wong, the functionality would essentially replicate what you can do with the Bitmoji extension for iMessage, and other messaging tools, which provides a range of Bitmoji stickers that you can use to respond to your regular messages.

Given such functionality is available outside of Snapchat, which owns Bitmoji, it would make sense for the app to enable the same reactions within Stories replies also. There's no word on any official release of this functionality as yet.
And lastly, Wong has also discovered a new Snapchat Events functionality in the back-end code of the app, which would enable users to create an Event - including a name, location and time - and facilitate a group chat for invitees.

The functionality seems like a more basic version of Facebook events - as noted here, invitees would be able to swipe up on an invite to join the related group chat, while you'd also expect there to be in-app reminders of upcoming events and other options to help maximize awareness among your group.
Given Snap's focus on connecting friends, group functionality also makes sense, and would be another helpful addition that would keep users on-platform longer, and more aligned to the app for their social connectivity.
Again, none of these features is being rolled out, they are all in test mode, but they would each add some small, but helpful, new functions to the Snap process, and all align with the company's broader goals for the app.
Given this, you can probably expect to see them launching soon - we'll keep you updated on any official updates as news comes to hand.