diff --git a/test-salt-formulas-env.groovy b/test-salt-formulas-env.groovy
index 53309c4..de631bf 100644
--- a/test-salt-formulas-env.groovy
+++ b/test-salt-formulas-env.groovy
@@ -23,7 +23,7 @@
 }
 
 env.GERRIT_BRANCH = 'master'
-if (env.GERRIT_PARENT_BRANCH) {
+if (common.validInputParam('GERRIT_PARENT_BRANCH')) {
   env.GERRIT_BRANCH = GERRIT_PARENT_BRANCH
 }