test_if1

defined (FALSE) (if test 1) defined (TRUE) (if test 2) defined (if test 3 level 1) defined (if test 3 level 2) defined (if test 3 level 3) defined (if test 3 level 4 FALSE) ------------------
defined (TRUE) (if test 1) defined (FALSE) (if test 2) defined (if test 3 level 1) defined (if test 3 level 2) defined (if test 3 level 3) defined (if test 3 level 4)