I did a recent shear test (destructive test), on a uBGA liken product, and noted the post-shear solder joint, had clean "smooth" visual appearance under the uBGA pad, however the matching pcb pad was clearly lifted clean.
Question: 1) how is solder joint supposed to seperate for a shear test?
1a) visual post-shear appears like two smooth plane-slide (shear)motion break?
1b) visual post-shear appears like "clayball" jagged (shear)break?
It depends on if  your solder connection is properly wetted or not and  the connection was sheared properly or not. For a properly wetted connection and properly run shear process, it looks like someone cut the connection with a knife.