busybox/shell/hush_test/hush-test2/andor1.tests

e=''
[[ a && b ]]	&& echo 1:YES
[[ a && '' ]]	|| echo 2:no
[[ a || b ]]	&& echo 3:YES
[[ '' || b ]]	&& echo 4:YES
[[ "" || "$e" ]]	|| echo 5:no
[[ "" || $e ]]	|| echo 6:no