Additional team and channel-related features and issues within Microsoft Teams for Education
Hello M439ca,
In my lab with Teams, we can only perform audio devices test via “Make a test call”, you may try that to check your audio devices (click your account tile on the top right of the corner, select Settings -> Devices ):
To test camera, there isn't directly way to perform a test, but you can start a video call and video meeting in Teams, and confirm with recipients whether they can see your video.
If you need any assistance, welcome back and let me know.
Kind Regards,
Anna