In the button pull test, the main body of the sample is the button attached to the sheet-like fabric or other materials. As long as the button can be matched with the fixture of the machine, there is no uniform requirement for the size and shape of the fabric to which the button is attached. You can use scissors to cut or use a blade to cut a piece of fabric with buttons of appropriate size as a sample (make the button as far as possible in the center of the sheet-like fabric).
Of course, if you want to test the holding strength of a button on a piece of clothing, you can even mount the tested area of the clothing directly on the corresponding fixture for on-site pull testing.