Spire test: It is a test carried out to remove Error due to non-perpendicularity of the horizontal axis and the vertical axis in surveying Instrument. 
Cross hair ring Test: This test is done to make the vertical cross hair lie in a plane perpendicular to the horizontal axis. 
Plate level Test: This test is done to make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical 
Vertical arc Test: This test is done to make the vertical circle indicate zero when the line of sight is perpendicular to the vertical axis