diff --git a/core/modules/system/tests/common.test b/core/modules/system/tests/common.test
index cc51a01..8fa9faf 100644
--- a/core/modules/system/tests/common.test
+++ b/core/modules/system/tests/common.test
@@ -2429,6 +2429,13 @@ class CommonFormatDateTestCase extends DrupalWebTestCase {
     );
     $this->drupalPost('admin/config/regional/date-time/types/add', $edit, t('Add date type'));
 
+    // Add a second date format with a different case than the first.
+    $admin_date_format = 'j M Y';
+    $edit = array('date_format' => $admin_date_format);
+    $this->drupalPost('admin/config/regional/date-time/formats/add', $edit, t('Add format'));
+    $this->assertText(t('Custom date format added.'));
+
+
     $timestamp = strtotime('2007-03-10T00:00:00+00:00');
     $this->assertIdentical(format_date($timestamp, 'example_style', '', 'America/Los_Angeles'), '9 Mar 07', t('Test format_date() using an admin-defined date type.'));
     $this->assertIdentical(format_date($timestamp, 'undefined_style'), format_date($timestamp, 'medium'), t('Test format_date() defaulting to medium when $type not found.'));