diff --git a/core/modules/views/src/Tests/ViewResultAssertionTrait.php b/core/modules/views/src/Tests/ViewResultAssertionTrait.php
index 00501f5..8ab752b 100644
--- a/core/modules/views/src/Tests/ViewResultAssertionTrait.php
+++ b/core/modules/views/src/Tests/ViewResultAssertionTrait.php
@@ -96,7 +96,8 @@ protected function assertIdenticalResultsetHelper($view, $expected_result, $colu
           if (count(explode(':', $view_column)) == 2) {
             $column = explode(':', $view_column)[1];
           }
-          $row[$expected_column] = $field->getValue($value, $column);
+          $field_value = $field->getValue($value, $column);
+          $row[$expected_column] = is_array($field_value) ? array_map('strval', $field_value) : (string) $field_value;
         }
       }
       $result[$key] = $row;