Doing an adhesion test is an important part of the preparation process prior to starting painting. The major reason for this is so that you know what ever the substrate you are applying the paint to is going to last and not just let go soon after you complete your painting project.
This is very easily done, all you have to do is cut through the surface to be painted onto in a crosshatch pattern then apply some masking tape over the area and pull off. If the paint comes off then you know that the surface isn’t sound for painting and may require the existing paintwork to be removed prior to painting.
It is suggested that the above mentioned test be performed in various areas to be painted.
At the same time you do the test it could be a good idea to do a Lead Paint Test.