diff --git a/tests/Bootstrap.php b/tests/Bootstrap.php
index ea8d8ae..8ce80b3 100644
--- a/tests/Bootstrap.php
+++ b/tests/Bootstrap.php
@@ -38,7 +38,7 @@
 
 // Prep our test environment
 include_once $dir.'/mocks/core/common.php';
-include_once SYSTEM_PATH.'core/common.php';
+include_once SYSTEM_PATH.'core/Common.php';
 include_once $dir.'/mocks/autoloader.php';
 spl_autoload_register('autoload');
 
diff --git a/tests/mocks/autoloader.php b/tests/mocks/autoloader.php
index 431c310..5b202f1 100644
--- a/tests/mocks/autoloader.php
+++ b/tests/mocks/autoloader.php
@@ -65,6 +65,12 @@
 			$dir = SYSTEM_PATH.'libraries'.DIRECTORY_SEPARATOR.$parent.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
 			$class = $subclass;
 		}
+		elseif (preg_match('/^CI_DB_(.+)_(.+)_(driver|forge|result|utility)$/', $class, $m) && count($m) === 4)
+		{
+			$driver_path = SYSTEM_PATH.'database'.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
+			$dir = $driver_path.$m[1].DIRECTORY_SEPARATOR.'subdrivers'.DIRECTORY_SEPARATOR;
+			$file = $dir.$m[1].'_'.$m[2].'_'.$m[3].'.php';
+		}
 		elseif (preg_match('/^CI_DB_(.+)_(driver|forge|result|utility)$/', $class, $m) && count($m) === 3)
 		{
 			$driver_path = SYSTEM_PATH.'database'.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
@@ -104,4 +110,4 @@
 	}
 
 	include_once($file);
-}
+}
\ No newline at end of file
diff --git a/tests/mocks/ci_testcase.php b/tests/mocks/ci_testcase.php
index 980e912..e581d4b 100644
--- a/tests/mocks/ci_testcase.php
+++ b/tests/mocks/ci_testcase.php
@@ -275,6 +275,16 @@
 	 */
 	public function ci_vfs_clone($path)
 	{
+		// Check for array
+		if (is_array($path))
+		{
+			foreach ($path as $file)
+			{
+				$this->ci_vfs_clone($file);
+			}
+			return;
+		}
+
 		// Get real file contents
 		$content = file_get_contents(PROJECT_BASE.$path);
 		if ($content === FALSE)
diff --git a/tests/mocks/database/db.php b/tests/mocks/database/db.php
index 7565853..7e0030e 100644
--- a/tests/mocks/database/db.php
+++ b/tests/mocks/database/db.php
@@ -8,6 +8,16 @@
 	private $config = array();
 
 	/**
+	 * @var string DB driver name
+	 */
+	private static $dbdriver = '';
+
+	/**
+	 * @var string DB sub-driver name
+	 */
+	private static $subdriver = '';
+
+	/**
 	 * Prepare database configuration skeleton
 	 *
 	 * @param  array 	DB configuration to set
@@ -31,6 +41,12 @@
 			throw new InvalidArgumentException('Group '.$group.' not exists');
 		}
 
+		self::$dbdriver = $this->config[$group]['dbdriver'];
+		if (isset($this->config[$group]['subdriver']))
+		{
+			self::$subdriver = $this->config[$group]['subdriver'];
+		}
+
 		$params = array(
 			'dbprefix' => '',
 			'pconnect' => FALSE,
@@ -50,7 +66,7 @@
 		$failover = empty($config['failover']) ? FALSE : $config['failover'];
 
 		$dsn = $config['dbdriver'].'://'.$config['username'].':'.$config['password']
-			       .'@'.$config['hostname'].'/'.$config['database'];
+					.'@'.$config['hostname'].'/'.$config['database'];
 
 		// Build the parameter
 		$other_params = array_slice($config, 6);
@@ -83,7 +99,32 @@
 	 */
 	public static function DB($group, $query_builder = FALSE)
 	{
-		include_once(BASEPATH.'database/DB.php');
+		// Create dummy driver and builder files to "load" - the mocks have
+		// already triggered autoloading of the real files
+		$case = CI_TestCase::instance();
+		$driver = self::$dbdriver;
+		$subdriver = self::$subdriver;
+		$case->ci_vfs_create(array(
+			'DB_driver.php' => '',
+			'DB_forge.php' => '',
+			'DB_query_builder.php' => ''
+		), '', $case->ci_base_root, 'database');
+		if (file_exists(SYSTEM_PATH.'database/drivers/'.$driver.'/'.$driver.'_driver.php'))
+		{
+			$case->ci_vfs_create(array(
+				$driver.'_driver.php' => '',
+				$driver.'_forge.php' => ''
+			), '', $case->ci_base_root, 'database/drivers/'.$driver);
+		}
+		if ($subdriver)
+		{
+			$case->ci_vfs_create(array(
+				$driver.'_'.$subdriver.'_driver.php' => '',
+				$driver.'_'.$subdriver.'_forge.php' => ''
+			), '', $case->ci_base_root, 'database/drivers/'.$driver.'/subdrivers');
+		}
+
+		include_once(SYSTEM_PATH.'database/DB.php');
 
 		try
 		{