t/test-lib.sh: Protect ourselves from common misconfiguration

that exports CDPATH to the environment
Signed-off-by: NJunio C Hamano <junkio@cox.net>

t/test-lib.sh

@@ -36,6 +36,10 @@ export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME
 export GIT_COMMITTER_EMAIL GIT_COMMITTER_NAME
 export EDITOR VISUAL
 
+# Protect ourselves from common misconfiguration to export
+# CDPATH into the environment
+unset CDPATH
+
 case $(echo $GIT_TRACE |tr "[A-Z]" "[a-z]") in
 	1|2|true)
 		echo "* warning: Some tests will not work if GIT_TRACE" \