+launched via the 'sh' command. The script should run the test and report
+the result by one of:
+
+ * for a test pass: exit with status 0
+ * where a test has been skipped (perhaps because it depends on an
+ external program which can't be found): print "Test $0 SKIP (reason)"
+ and exit with status 120
+ * for a test fail: exit with some status other than 0 or 120