diff -u b/core/modules/system/src/Tests/Module/UninstallTest.php b/core/modules/system/src/Tests/Module/UninstallTest.php
--- b/core/modules/system/src/Tests/Module/UninstallTest.php
+++ b/core/modules/system/src/Tests/Module/UninstallTest.php
@@ -129,5 +129,5 @@
     $edit = array();
     $this->drupalPostForm('admin/modules/uninstall', $edit, t('Uninstall'));
-    $this->assertText(t('No modules selected. '), 'No module is selected to uninstall');
+    $this->assertText(t('No modules selected.'), 'No module is selected to uninstall');
   }
 }