Add checks for programs which are required for the test suite to run. All prerequisite programs are checked for existance, and if any are missing, a list of missing programs is printed, and the test suite is aborted. All programs currently used in the tests, except those in core-utils, are checked.

#!/bin/sh

hg init
echo "[hooks]" > .hg/hgrc
echo 'precommit = echo precommit hook' >> .hg/hgrc
echo 'commit = echo commit hook: $NODE' >> .hg/hgrc
echo a > a
hg add a
hg commit -m "test" -d "0 0"