test_include1
undefined (TRUE), so including test_if2 ...
test_if2
undefined (TRUE)
(if test 1)
VAR2 defined (TRUE)
(if test 2)
defined (if test 3 level 1) VISIBLE
VAR2 VISIBLE (if test 3 level 2)
VAR2 defined VISIBLE (if test 3 level 3)
--- visible ---
END test_if2
(include test 1)