Feature request - ganged file test switches

[Steve Simmons]

Advance apologies if this has already been discussed and rejected.

It would be nice to have ganged file test switches. As an example, to test that 
a directory exists and is properly accessible one could do

  if [[ -d foo ]] && [[ -r foo ]] && [[ -x foo ]] ; then . . .

but

  if [[ -drx foo ]] ; then . . .

is a lot easier.

Best,

Steve