diff --git a/core/modules/simpletest/src/Tests/SimpleTestTest.php b/core/modules/simpletest/src/Tests/SimpleTestTest.php
index 8785897014ef470aa74bba1d13b4cb06e736834a..41d114ea6d10ef9c9c37d2efdcb5d858f9cd5bb6 100644
--- a/core/modules/simpletest/src/Tests/SimpleTestTest.php
+++ b/core/modules/simpletest/src/Tests/SimpleTestTest.php
@@ -174,7 +174,7 @@ function stubTest() {
     }
     catch (\AssertionError $e) {
       try {
-        // Now test with an error message to insure it is correctly passed
+        // Now test with an error message to ensure it is correctly passed
         // along by the rethrow.
         assert(FALSE, 'Lorem Ipsum');
       }