diff --git a/tests/lib.sh b/tests/lib.sh
index 00f23f1..6f0c6ee 100644
--- a/tests/lib.sh
+++ b/tests/lib.sh
@@ -1,3 +1,4 @@
+# shellcheck shell=bash
 # Shared helpers for tests/test_*.sh functional tests.
 # Meant to be sourced, not executed directly.