tests: Don't crash if unbuffer isn't installed

diff --git a/tests/tests.sh b/tests/tests.sh
index 662efd94a441c008ab817da1376b8a770f1f63a9..f233f7437596ef1ebdeb45a278303e0b8c13fb2e 100755 (executable)
--- a/tests/tests.sh
+++ b/tests/tests.sh
@@ -495,7 +495,7 @@ elif command -v expect_unbuffer &>/dev/null; then
 fi
 
 function bfs_pty() {
-    test -n "$UNBUFFER" || skip
+    test -n "${UNBUFFER:-}" || skip
 
     bfs_verbose "$@"
     "$UNBUFFER" bash -c 'stty cols 80 rows 24 && "$@"' bash "${BFS[@]}" "$@"