I am a member of team 7790, Baywatch Robotics.
Here is a 3D printable block to hold swerve modules in place when doing a swerve characterization. You should be able to easily print this and then run your program after disconnecting your turning motor.
Print settings
20% Infill
No Supports
Rotate prior to print to put long flat face on bed
Thank you for this great resource! Our team is new to using a holder to restrain the module while characterizing (we just let it run on the ground), could you please explain how it works? Some graphics / images would be nice!