diff --git a/t/t0006-date.sh b/t/t0006-date.sh
index 04ce53509c..d1856402b7 100755
--- a/t/t0006-date.sh
+++ b/t/t0006-date.sh
@@ -48,10 +48,17 @@ check_show default "$TIME" 'Wed Jun 15 16:13:20 2016 +0200'
 check_show raw "$TIME" '1466000000 +0200'
 check_show iso-local "$TIME" '2016-06-15 14:13:20 +0000'
 
-# arbitrary time absurdly far in the future
-FUTURE="5758122296 -0400"
-check_show iso       "$FUTURE" "2152-06-19 18:24:56 -0400"
-check_show iso-local "$FUTURE" "2152-06-19 22:24:56 +0000"
+case "$(test-date show:iso 9999999999)" in
+*2038*)
+	# on this platform, unsigned long is 32-bit, i.e. not large enough
+	;;
+*)
+	# arbitrary time absurdly far in the future
+	FUTURE="5758122296 -0400"
+	check_show iso       "$FUTURE" "2152-06-19 18:24:56 -0400"
+	check_show iso-local "$FUTURE" "2152-06-19 22:24:56 +0000"
+	;;
+esac
 
 check_parse() {
 	echo "$1 -> $2" >expect