diff --git a/tests/external_test.php b/tests/external_test.php
index bfa72f6..efa0f5d 100644
--- a/tests/external_test.php
+++ b/tests/external_test.php
@@ -27,6 +27,13 @@
  */
 class external_test extends \advanced_testcase {
 
+    public function setUp(): void {
+        global $SCRIPT;
+        // With @runTestsInSeparateProcesses, if you have auth_saml installed
+        // then it gives an error about $SCRIPT being null.
+        $SCRIPT = '';
+    }
+
     public function test_get_sharable_question_choices_working(): void {
 
         $this->resetAfterTest();