This would mean users would be able to send a message and have it disappear into thin air after a set period of time.
According to WABetaInfo, it can currently be set to 5 seconds or an hour and is only available in group chats.
This could all change should the feature be made available to all users not just those on beta.
The website also has no idea on when the option would be rolled out.
The latest test comes after it was revealed WhatsApp is working on a Boomerang-style feature.
Facebook own the messaging service and Instagram, whose Boomerang creator is used on their Instagram Stories and enables users to create a looping image that goes backwards and forwards.
The tool has been popular since its launch in 2016, and according to WhatsApp specialists WABetaInfo, it's in the testing stage and could be on the way in an update soon.
They wrote: "The option will be available in the Video Type panel (the same that allows the user to convert a video to GIF) when the video is less than 7 seconds, and it can be used to easily create a boomerang of your videos, to send to your contacts and as a status update."