+ - test_set_prereq SOME_PREREQ
+
+ Set a test prerequisite to be used later with test_have_prereq. The
+ test-lib will set some prerequisites for you, e.g. PERL and PYTHON
+ which are derived from ./GIT-BUILD-OPTIONS (grep test_set_prereq
+ test-lib.sh for more). Others you can set yourself and use later
+ with either test_have_prereq directly, or the three argument
+ invocation of test_expect_success and test_expect_failure.
+
+ - test_have_prereq SOME PREREQ
+
+ Check if we have a prerequisite previously set with
+ test_set_prereq. The most common use of this directly is to skip
+ all the tests if we don't have some essential prerequisite:
+
+ if ! test_have_prereq PERL
+ then
+ skip_all='skipping perl interface tests, perl not available'
+ test_done
+ fi
+