diff --git a/t/test-lib.sh b/t/test-lib.sh
index 86d77c16dd..d5f2b70bce 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -624,9 +624,9 @@ test_run_ () {
 		trace=
 		# 117 is magic because it is unlikely to match the exit
 		# code of other programs
-		test_eval_ "(exit 117) && $1"
-		if test "$?" != 117; then
-			error "bug in the test script: broken &&-chain: $1"
+		if test "OK-117" != "$(test_eval_ "(exit 117) && $1${LF}${LF}echo OK-\$?" 3>&1)"
+		then
+			error "bug in the test script: broken &&-chain or run-away HERE-DOC: $1"
 		fi
 		trace=$trace_tmp
 	fi