diff -u b/core/lib/Drupal/Core/Database/Connection.php b/core/lib/Drupal/Core/Database/Connection.php
--- b/core/lib/Drupal/Core/Database/Connection.php
+++ b/core/lib/Drupal/Core/Database/Connection.php
@@ -492,7 +492,7 @@
    *   An associative array of options to control how the query is run. See
    *   the documentation for DatabaseConnection::defaultOptions() for details.
    *
-   * @return Drupal\Core\Database\StatementInterface
+   * @return \Drupal\Core\Database\StatementInterface
    *   This method will return one of: the executed statement, the number of
    *   rows affected by the query (not the number matched), or the generated
    *   insert ID of the last query, depending on the value of
@@ -502,7 +502,7 @@
    *   $options['throw_exception'] is TRUE.
    *
    * @throws PDOException
-   * @throws Drupal\Core\Database\IntegrityConstraintViolationException
+   * @throws \Drupal\Core\Database\IntegrityConstraintViolationException
    */
   public function query($query, array $args = array(), $options = array()) {
 
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/system/lib/Drupal/system/Tests/Database/DatabaseExceptionWrapperTest.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * @file
+ * Contains Drupal\system\Tests\Database\DatabaseExceptionWrapperTest.
+ */
+
+namespace Drupal\system\Tests\Database;
+
+use Drupal\Core\Database\DatabaseExceptionWrapper;
+use Drupal\Core\Database\Database;
+use Drupal\simpletest\UnitTestBase;
+
+/**
+ * Tests DatabaseExceptionWrapper thrown.
+ */
+class DatabaseExceptionWrapperTest extends UnitTestBase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Database exceptiontests',
+      'description' => 'Tests exceptions thrown by queries.',
+      'group' => 'Database',
+    );
+  }
+
+  function testDatabaseExceptionWrapper() {
+    $connection = Database::getConnection();
+    $query = $connection->prepare('bananas');
+    try {
+      $connection->query($query);
+      $this->fail('The expected exception is not thrown.');
+    }
+    catch (DatabaseExceptionWrapper $e) {
+      $this->pass('The expected exception has been thrown.');
+    }
+  }
+
+}