diff --git a/system/core/Loader.php b/system/core/Loader.php
index 75e9360..ed830e2 100644
--- a/system/core/Loader.php
+++ b/system/core/Loader.php
@@ -1140,13 +1140,16 @@
 	 */
 	protected function _ci_autoloader()
 	{
-		if (defined('ENVIRONMENT') && file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload.php'))
+		// Get autoloader file from config path
+		$CI =& get_instance();
+		$path = reset($CI->config->_config_paths).'config/';
+		if (defined('ENVIRONMENT') && file_exists($path.ENVIRONMENT.'/autoload.php'))
 		{
-			include(APPPATH.'config/'.ENVIRONMENT.'/autoload.php');
+			include($path.ENVIRONMENT.'/autoload.php');
 		}
 		else
 		{
-			include(APPPATH.'config/autoload.php');
+			include($path.'autoload.php');
 		}
 
 		if ( ! isset($autoload))
@@ -1166,7 +1169,6 @@
 		// Load any custom config file
 		if (count($autoload['config']) > 0)
 		{
-			$CI =& get_instance();
 			foreach ($autoload['config'] as $key => $val)
 			{
 				$CI->config->load($val);
@@ -1275,4 +1277,4 @@
 }
 
 /* End of file Loader.php */
-/* Location: ./system/core/Loader.php */
\ No newline at end of file
+/* Location: ./system/core/Loader.php */
diff --git a/tests/Bootstrap.php b/tests/Bootstrap.php
index 1c666d5..ea8d8ae 100644
--- a/tests/Bootstrap.php
+++ b/tests/Bootstrap.php
@@ -8,10 +8,7 @@
 
 // Path constants
 defined('PROJECT_BASE') OR define('PROJECT_BASE', realpath($dir.'/../').'/');
-defined('BASEPATH') OR define('BASEPATH', PROJECT_BASE.'system/');
-defined('APPPATH') OR define('APPPATH', PROJECT_BASE.'application/');
-defined('VIEWPATH') OR define('VIEWPATH', PROJECT_BASE.'');
-isset($_SERVER['REMOTE_ADDR']) OR $_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+defined('SYSTEM_PATH') OR define('SYSTEM_PATH', PROJECT_BASE.'system/');
 
 // Get vfsStream either via PEAR or composer
 foreach (explode(PATH_SEPARATOR, get_include_path()) as $path)
@@ -31,8 +28,17 @@
 	class_alias('org\bovigo\vfs\vfsStreamWrapper', 'vfsStreamWrapper');
 }
 
+// Define CI path constants to VFS (filesystem setup in CI_TestCase::setUp)
+defined('BASEPATH') OR define('BASEPATH', vfsStream::url('system/'));
+defined('APPPATH') OR define('APPPATH', vfsStream::url('application/'));
+defined('VIEWPATH') OR define('VIEWPATH', APPPATH.'views/');
+
+// Set localhost "remote" IP
+isset($_SERVER['REMOTE_ADDR']) OR $_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+
 // Prep our test environment
 include_once $dir.'/mocks/core/common.php';
+include_once SYSTEM_PATH.'core/common.php';
 include_once $dir.'/mocks/autoloader.php';
 spl_autoload_register('autoload');
 
diff --git a/tests/codeigniter/core/Config_test.php b/tests/codeigniter/core/Config_test.php
index 30cb90a..7782a78 100644
--- a/tests/codeigniter/core/Config_test.php
+++ b/tests/codeigniter/core/Config_test.php
@@ -90,4 +90,54 @@
 		$this->assertEquals('http://example.com/system/', $this->config->system_url());
 	}
 
-}
\ No newline at end of file
+	// --------------------------------------------------------------------
+
+	public function test_load()
+	{
+		// Create VFS tree of application config files
+		$file1 = 'test.php';
+		$file2 = 'secttest';
+		$key1 = 'testconfig';
+		$val1 = 'my_value';
+		$cfg1 = array(
+			$key1 => $val1
+		);
+		$cfg2 = array(
+			'one' => 'prime',
+			'two' => 2,
+			'three' => true
+		);
+		$tree = array(
+			'application' => array(
+				'config' => array(
+					$file1 => '<?php $config = '.var_export($cfg1, TRUE).';',
+					$file2.'.php' => '<?php $config = '.var_export($cfg2, TRUE).';'
+				)
+			)
+		);
+		$root = vfsStream::setup('root', NULL, $tree);
+
+		// Set config path with VFS URL
+		$this->config->_config_paths = array(vfsStream::url('application').'/');
+
+		// Test regular load
+		$this->assertTrue($this->config->load($file1));
+		$this->assertEquals($val1, $this->config->item($key1));
+
+		// Test section load
+		$this->assertTrue($this->config->load($file2, TRUE));
+		$this->assertEquals($cfg2, $this->config->item($file2));
+
+		// Test graceful fail
+		$this->assertFalse($this->config->load('not_config_file', FALSE, TRUE));
+
+		// Test regular fail
+		$file3 = 'absentia';
+		$this->setExpectedException(
+			'RuntimeException',
+			'CI Error: The configuration file '.$file3.'.php does not exist.'
+		);
+		$this->assertNull($this->config->load($file3));
+	}
+
+}
diff --git a/tests/codeigniter/core/Lang_test.php b/tests/codeigniter/core/Lang_test.php
index a410dab..3364362 100644
--- a/tests/codeigniter/core/Lang_test.php
+++ b/tests/codeigniter/core/Lang_test.php
@@ -17,6 +17,7 @@
 
 	public function test_load()
 	{
+		$this->ci_vfs_clone('system/language/english/profiler_lang.php');
 		$this->assertTrue($this->lang->load('profiler', 'english'));
 		$this->assertEquals('URI STRING', $this->lang->line('profiler_uri_string'));
 	}
@@ -25,6 +26,7 @@
 
 	public function test_load_with_unspecified_language()
 	{
+		$this->ci_vfs_clone('system/language/english/profiler_lang.php');
 		$this->assertTrue($this->lang->load('profiler'));
 		$this->assertEquals('URI STRING', $this->lang->line('profiler_uri_string'));
 	}
diff --git a/tests/codeigniter/core/Loader_test.php b/tests/codeigniter/core/Loader_test.php
index fdea962..69b2afb 100644
--- a/tests/codeigniter/core/Loader_test.php
+++ b/tests/codeigniter/core/Loader_test.php
@@ -9,63 +9,122 @@
 		// Instantiate a new loader
 		$this->load = new Mock_Core_Loader();
 
-		// mock up a ci instance
-		$this->ci_obj = new stdClass;
+		// Get CI instance
+		$this->ci_obj = $this->ci_instance();
 
-		// Fix get_instance()
-		$this->ci_instance($this->ci_obj);
+		// Set subclass prefix
+		$this->ci_set_config('subclass_prefix', 'MY_');
 	}
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::library
+	 */
 	public function test_library()
 	{
-		$this->_setup_config_mock();
+		// Create libraries directory with test library
+		$lib = 'unit_test_lib';
+		$class = 'CI_'.ucfirst($lib);
+		$this->ci_vfs_create($lib, '<?php class '.$class.' { }', $this->ci_base_root, 'libraries');
 
 		// Test loading as an array.
-		$this->assertNull($this->load->library(array('table')));
-		$this->assertTrue(class_exists('CI_Table'), 'Table class exists');
-		$this->assertAttributeInstanceOf('CI_Table', 'table', $this->ci_obj);
+		$this->assertNull($this->load->library(array($lib)));
+		$this->assertTrue(class_exists($class), $class.' does not exist');
+		$this->assertAttributeInstanceOf($class, $lib, $this->ci_obj);
 
 		// Test no lib given
-		$this->assertEquals(FALSE, $this->load->library());
+		$this->assertFalse($this->load->library());
 
 		// Test a string given to params
-		$this->assertEquals(NULL, $this->load->library('table', ' '));
+		$this->assertNull($this->load->library($lib, ' '));
 	}
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::library
+	 */
+	public function test_library_config()
+	{
+		// Create libraries directory with test library
+		$lib = 'unit_test_config_lib';
+		$class = 'CI_'.ucfirst($lib);
+		$content = '<?php class '.$class.' { public function __construct($params) { $this->config = $params; } }';
+		$this->ci_vfs_create($lib, $content, $this->ci_base_root, 'libraries');
+
+		// Create config file
+		$cfg = array(
+			'foo' => 'bar',
+			'bar' => 'baz',
+			'baz' => false
+		);
+		$this->ci_vfs_create($lib, '<?php $config = '.var_export($cfg, TRUE).';', $this->ci_app_root, 'config');
+
+		// Test object name and config
+		$obj = 'testy';
+		$this->assertNull($this->load->library($lib, NULL, $obj));
+		$this->assertTrue(class_exists($class), $class.' does not exist');
+		$this->assertAttributeInstanceOf($class, $obj, $this->ci_obj);
+		$this->assertEquals($cfg, $this->ci_obj->$obj->config);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * @covers CI_Loader::library
+	 */
 	public function test_load_library_in_application_dir()
 	{
-		$this->_setup_config_mock();
+		// Create libraries directory in app path with test library
+		$lib = 'super_test_library';
+		$class = ucfirst($lib);
+		$this->ci_vfs_create($lib, '<?php class '.$class.' { }', $this->ci_app_root, 'libraries');
 
-		$content = '<?php class Super_test_library {} ';
-
-		$model = vfsStream::newFile('Super_test_library.php')->withContent($content)->at($this->load->libs_dir);
-		$this->assertNull($this->load->library('super_test_library'));
+		// Load library
+		$this->assertNull($this->load->library($lib));
 
 		// Was the model class instantiated.
-		$this->assertTrue(class_exists('Super_test_library'));
+		$this->assertTrue(class_exists($class), $class.' does not exist');
+		$this->assertAttributeInstanceOf($class, $lib, $this->ci_obj);
 	}
 
 	// --------------------------------------------------------------------
 
-	private function _setup_config_mock()
+	/**
+	 * @covers CI_Loader::driver
+	 */
+	public function test_driver()
 	{
-		// Mock up a config object until we
-		// figure out how to test the library configs
-		$config = $this->getMock('CI_Config', NULL, array(), '', FALSE);
-		$config->expects($this->any())
-			   ->method('load')
-			   ->will($this->returnValue(TRUE));
+		// Create libraries directory with test driver
+		$driver = 'unit_test_driver';
+		$dir = ucfirst($driver);
+		$class = 'CI_'.$dir;
+		$content = '<?php class '.$class.' { } ';
+		$this->ci_vfs_create($driver, $content, $this->ci_base_root, 'libraries/'.$dir);
 
-		// Add the mock to our stdClass
-		$this->ci_instance_var('config', $config);
+		// Test loading as an array.
+		$this->assertNull($this->load->driver(array($driver)));
+		$this->assertTrue(class_exists($class), $class.' does not exist');
+		$this->assertAttributeInstanceOf($class, $driver, $this->ci_obj);
+
+		// Test loading as a library with a name
+		$obj = 'testdrive';
+		$this->assertNull($this->load->library($driver, NULL, $obj));
+		$this->assertAttributeInstanceOf($class, $obj, $this->ci_obj);
+
+		// Test no driver given
+		$this->assertFalse($this->load->driver());
+
+		// Test a string given to params
+		$this->assertNull($this->load->driver($driver, ' '));
 	}
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::model
+	 */
 	public function test_non_existent_model()
 	{
 		$this->setExpectedException(
@@ -79,20 +138,23 @@
 	// --------------------------------------------------------------------
 
 	/**
-	 * @coverts CI_Loader::model
+	 * @covers CI_Loader::model
 	 */
 	public function test_models()
 	{
 		$this->ci_set_core_class('model', 'CI_Model');
 
-		$content = '<?php class Unit_test_model extends CI_Model {} ';
+		// Create models directory with test model
+		$model = 'unit_test_model';
+		$class = ucfirst($model);
+		$content = '<?php class '.$class.' extends CI_Model {} ';
+		$this->ci_vfs_create($model, $content, $this->ci_app_root, 'models');
 
-		$model = vfsStream::newFile('unit_test_model.php')->withContent($content)->at($this->load->models_dir);
-
-		$this->assertNull($this->load->model('unit_test_model'));
+		// Load model
+		$this->assertNull($this->load->model($model));
 
 		// Was the model class instantiated.
-		$this->assertTrue(class_exists('Unit_test_model'));
+		$this->assertTrue(class_exists($class));
 
 		// Test no model given
 		$this->assertNull($this->load->model(''));
@@ -109,26 +171,27 @@
 	// --------------------------------------------------------------------
 
 	/**
-	 * @coverts CI_Loader::view
+	 * @covers CI_Loader::view
 	 */
 	public function test_load_view()
 	{
 		$this->ci_set_core_class('output', 'CI_Output');
 
+		// Create views directory with test view
+		$view = 'unit_test_view';
 		$content = 'This is my test page.  <?php echo $hello; ?>';
-		$view = vfsStream::newFile('unit_test_view.php')->withContent($content)->at($this->load->views_dir);
+		$this->ci_vfs_create($view, $content, $this->ci_app_root, 'views');
 
 		// Use the optional return parameter in this test, so the view is not
 		// run through the output class.
-		$this->assertEquals('This is my test page.  World!',
-		$this->load->view('unit_test_view', array('hello' => "World!"), TRUE));
-
+		$out = $this->load->view($view, array('hello' => "World!"), TRUE);
+		$this->assertEquals('This is my test page.  World!', $out);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * @coverts CI_Loader::view
+	 * @covers CI_Loader::view
 	 */
 	public function test_non_existent_view()
 	{
@@ -142,16 +205,22 @@
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::file
+	 */
 	public function test_file()
 	{
+		// Create views directory with test file
+		$dir = 'views';
+		$file = 'ci_test_mock_file';
 		$content = 'Here is a test file, which we will load now.';
-		$file = vfsStream::newFile('ci_test_mock_file.php')->withContent($content)->at($this->load->views_dir);
+		$this->ci_vfs_create($file, $content, $this->ci_app_root, $dir);
 
 		// Just like load->view(), take the output class out of the mix here.
-		$load = $this->load->file(vfsStream::url('application').'/views/ci_test_mock_file.php', TRUE);
+		$out = $this->load->file(APPPATH.$dir.'/'.$file.'.php', TRUE);
+		$this->assertEquals($content, $out);
 
-		$this->assertEquals($content, $load);
-
+		// Test non-existent file
 		$this->setExpectedException(
 			'RuntimeException',
 			'CI Error: Unable to load the requested file: ci_test_file_not_exists'
@@ -162,6 +231,9 @@
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::vars
+	 */
 	public function test_vars()
 	{
 		$this->assertNull($this->load->vars(array('foo' => 'bar')));
@@ -170,10 +242,22 @@
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::helper
+	 */
 	public function test_helper()
 	{
-		$this->assertEquals(NULL, $this->load->helper('array'));
+		// Create helper directory in app path with test helper
+		$helper = 'test';
+		$func = '_my_helper_test_func';
+		$content = '<?php function '.$func.'() { return true; } ';
+		$this->ci_vfs_create($helper.'_helper', $content, $this->ci_app_root, 'helpers');
 
+		// Load helper
+		$this->assertEquals(NULL, $this->load->helper($helper));
+		$this->assertTrue(function_exists($func), $func.' does not exist');
+
+		// Test non-existent helper
 		$this->setExpectedException(
 			'RuntimeException',
 			'CI Error: Unable to load the requested file: helpers/bad_helper.php'
@@ -184,9 +268,31 @@
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::helper
+	 */
 	public function test_loading_multiple_helpers()
 	{
-		$this->assertEquals(NULL, $this->load->helpers(array('file', 'array', 'string')));
+		// Create helper directory in base path with test helpers
+		$helpers = array();
+		$funcs = array();
+		$files = array();
+		for ($i = 1; $i <= 3; ++$i) {
+			$helper = 'test'.$i;
+			$helpers[] = $helper;
+			$func = '_my_helper_test_func'.$i;
+			$funcs[] = $func;
+			$files[$helper.'_helper'] = '<?php function '.$func.'() { return true; } ';
+		}
+		$this->ci_vfs_create($files, NULL, $this->ci_base_root, 'helpers');
+
+		// Load helpers
+		$this->assertEquals(NULL, $this->load->helpers($helpers));
+
+		// Verify helper existence
+		foreach ($funcs as $func) {
+			$this->assertTrue(function_exists($func), $func.' does not exist');
+		}
 	}
 
 	// --------------------------------------------------------------------
@@ -198,24 +304,117 @@
 
 	// --------------------------------------------------------------------
 
+	/**
+	 * @covers CI_Loader::add_package_path
+	 * @covers CI_Loader::get_package_paths
+	 * @covers CI_Loader::remove_package_path
+	 */
+	public function test_packages()
+	{
+		// Create third-party directory in app path with model
+		$dir = 'third-party';
+		$lib = 'unit_test_package';
+		$class = 'CI_'.ucfirst($lib);
+		$content = '<?php class '.$class.' { } ';
+		$this->ci_vfs_create($lib, $content, $this->ci_app_root, $dir);
+
+		// Test failed load without path
+		$this->setExpectedException(
+			'RuntimeException',
+			'CI Error: Unable to load the requested class: '.$lib
+		);
+		$this->load->library($lib);
+
+		// Clear exception and get paths
+		$this->setExpectedException(NULL);
+		$paths = $this->load->get_package_paths(TRUE);
+
+		// Add path and verify
+		$path = APPPATH.$dir;
+		$this->assertNull($this->load->add_package_path($path));
+		$this->assertContains($path, $this->load->get_package_paths(TRUE));
+
+		// Test successful load
+		$this->assertNull($this->load->library($lib));
+		$this->assertTrue(class_exists($class), $class.' does not exist');
+
+		// Remove path and verify restored paths
+		$this->assertNull($this->load->remove_package_path($path));
+		$this->assertEquals($paths, $this->load->get_package_paths(TRUE));
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * @covers CI_Loader::config
+	 */
 	public function test_load_config()
 	{
-		$this->_setup_config_mock();
 		$this->assertNull($this->load->config('config', FALSE));
 	}
 
 	// --------------------------------------------------------------------
 
-	public function test_load_bad_config()
+	/**
+	 * @covers CI_Loader::_ci_autoloader
+	 */
+	public function test_autoloader()
 	{
-		$this->_setup_config_mock();
+		// Create helper directory in app path with test helper
+		$helper = 'autohelp';
+		$hlp_func = '_autohelp_test_func';
+		$content = '<?php function '.$hlp_func.'() { return true; } ';
+		$this->ci_vfs_create($helper.'_helper', $content, $this->ci_app_root, 'helpers');
 
-		$this->setExpectedException(
-			'RuntimeException',
-			'CI Error: The configuration file foobar.php does not exist.'
+		// Create libraries directory in base path with test library
+		$lib = 'autolib';
+		$lib_class = 'CI_'.ucfirst($lib);
+		$this->ci_vfs_create($lib, '<?php class '.$lib_class.' { }', $this->ci_base_root, 'libraries');
+
+		// Create test driver
+		$drv = 'autodrv';
+		$subdir = ucfirst($drv);
+		$drv_class = 'CI_'.$subdir;
+		$this->ci_vfs_create($drv, '<?php class '.$drv_class.' { }', $this->ci_base_root, 'libraries/'.$subdir);
+
+		// Create package directory in app path with model
+		$dir = 'testdir';
+		$path = APPPATH.$dir.'/';
+		$model = 'automod';
+		$mod_class = ucfirst($model);
+		$this->ci_vfs_create($model, '<?php class '.$mod_class.' { }', $this->ci_app_root, $dir.'/models');
+
+		// Create autoloader config
+		$cfg = array(
+			'packages' => array($path),
+			'helper' => array($helper),
+			'libraries' => array($lib),
+			'drivers' => array($drv),
+			'model' => array($model),
+			'config' => array()
 		);
+		$this->ci_vfs_create('autoload', '<?php $autoload = '.var_export($cfg, TRUE).';', $this->ci_app_root, 'config');
 
-		$this->load->config('foobar', FALSE);
+		// Run autoloader
+		$this->load->autoload();
+
+		// Verify path
+		$this->assertContains($path, $this->load->get_package_paths());
+
+		// Verify helper
+		$this->assertTrue(function_exists($hlp_func), $hlp_func.' does not exist');
+
+		// Verify library
+		$this->assertTrue(class_exists($lib_class), $lib_class.' does not exist');
+		$this->assertAttributeInstanceOf($lib_class, $lib, $this->ci_obj);
+
+		// Verify driver
+		$this->assertTrue(class_exists($drv_class), $drv_class.' does not exist');
+		$this->assertAttributeInstanceOf($drv_class, $drv, $this->ci_obj);
+
+		// Verify model
+		$this->assertTrue(class_exists($mod_class), $mod_class.' does not exist');
+		$this->assertAttributeInstanceOf($mod_class, $model, $this->ci_obj);
 	}
 
 }
\ No newline at end of file
diff --git a/tests/codeigniter/helpers/date_helper_test.php b/tests/codeigniter/helpers/date_helper_test.php
index 9feade7..1458acd 100644
--- a/tests/codeigniter/helpers/date_helper_test.php
+++ b/tests/codeigniter/helpers/date_helper_test.php
@@ -168,6 +168,8 @@
 
 	public function test_timespan()
 	{
+		$this->ci_vfs_clone('system/language/english/date_lang.php');
+
 		$loader_cls = $this->ci_core_class('load');
 		$this->ci_instance_var('load', new $loader_cls);
 
diff --git a/tests/codeigniter/helpers/form_helper_test.php b/tests/codeigniter/helpers/form_helper_test.php
index 1a30ed9..48628d2 100644
--- a/tests/codeigniter/helpers/form_helper_test.php
+++ b/tests/codeigniter/helpers/form_helper_test.php
@@ -1,10 +1,12 @@
 <?php
 
-require BASEPATH . 'core/Common.php';
-require BASEPATH . 'helpers/form_helper.php';
-
 class Form_helper_test extends CI_TestCase
 {
+	public function set_up()
+	{
+		$this->helper('form');
+	}
+
 	public function test_form_hidden()
 	{
 		$expected = <<<EOH
diff --git a/tests/codeigniter/helpers/number_helper_test.php b/tests/codeigniter/helpers/number_helper_test.php
index ef6aae1..817db2c 100644
--- a/tests/codeigniter/helpers/number_helper_test.php
+++ b/tests/codeigniter/helpers/number_helper_test.php
@@ -11,31 +11,18 @@
 
 		// Mock away load, too much going on in there,
 		// we'll just check for the expected parameter
-
 		$lang = $this->getMock($lang_cls, array('load'));
 		$lang->expects($this->once())
 			 ->method('load')
 			 ->with($this->equalTo('number'));
 
 		// Assign the proper language array
-
-		$lang->language = $this->_get_lang('number');
+		$lang->language = $this->lang('number');
 
 		// We don't have a controller, so just create
 		// a cheap class to act as our super object.
 		// Make sure it has a lang attribute.
-
-		$obj = new stdClass;
-		$obj->lang = $lang;
-		$this->ci_instance($obj);
-	}
-
-	// Quick helper to actually grab the language
-	// file. Consider moving this to ci_testcase?
-	public function _get_lang($name)
-	{
-		require BASEPATH.'language/english/'.$name.'_lang.php';
-		return $lang;
+		$this->ci_instance_var('lang', $lang);
 	}
 
 	public function test_byte_format()
diff --git a/tests/codeigniter/helpers/text_helper_test.php b/tests/codeigniter/helpers/text_helper_test.php
index f131469..d75d262 100644
--- a/tests/codeigniter/helpers/text_helper_test.php
+++ b/tests/codeigniter/helpers/text_helper_test.php
@@ -64,6 +64,7 @@
 
 	public function test_convert_accented_characters()
 	{
+		$this->ci_vfs_clone('application/config/foreign_chars.php');
 		$this->assertEquals('AAAeEEEIIOOEUUUeY', convert_accented_characters('ÀÂÄÈÊËÎÏÔŒÙÛÜŸ'));
 		$this->assertEquals('a e i o u n ue', convert_accented_characters('á é í ó ú ñ ü'));
 	}
diff --git a/tests/codeigniter/libraries/Encrypt_test.php b/tests/codeigniter/libraries/Encrypt_test.php
index 153a25e..998d806 100644
--- a/tests/codeigniter/libraries/Encrypt_test.php
+++ b/tests/codeigniter/libraries/Encrypt_test.php
@@ -4,11 +4,8 @@
 
 	public function set_up()
 	{
-		$obj = new stdClass;
-		$obj->encrypt = new Mock_Libraries_Encrypt();
-
-		$this->ci_instance($obj);
-		$this->encrypt = $obj->encrypt;
+		$this->encrypt = new Mock_Libraries_Encrypt();
+		$this->ci_instance_var('encrypt', $this->encrypt);
 
 		$this->ci_set_config('encryption_key', "Encryptin'glike@boss!");
 		$this->msg = 'My secret message';
diff --git a/tests/codeigniter/libraries/Parser_test.php b/tests/codeigniter/libraries/Parser_test.php
index b68f44a..394c226 100644
--- a/tests/codeigniter/libraries/Parser_test.php
+++ b/tests/codeigniter/libraries/Parser_test.php
@@ -4,12 +4,8 @@
 
 	public function set_up()
 	{
-		$obj = new stdClass;
-		$obj->parser = new Mock_Libraries_Parser();
-
-		$this->ci_instance($obj);
-
-		$this->parser = $obj->parser;
+		$this->parser = new Mock_Libraries_Parser();
+		$this->ci_instance_var('parser', $this->parser);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/tests/codeigniter/libraries/Session_test.php b/tests/codeigniter/libraries/Session_test.php
index 60d3a5b..14469f7 100644
--- a/tests/codeigniter/libraries/Session_test.php
+++ b/tests/codeigniter/libraries/Session_test.php
@@ -29,13 +29,15 @@
 		$_COOKIE = array();
 
 		// Establish necessary support classes
-		$obj = new stdClass;
 		$cfg = $this->ci_core_class('cfg');
-		$obj->config = new $cfg();
 		$ldr = $this->ci_core_class('load');
-		$obj->load = new $ldr();
-		$obj->input = new Mock_Core_Input(NULL, NULL);
-		$this->ci_instance($obj);
+		$ci = $this->ci_instance();
+		$ci->config = new $cfg();
+		$ci->load = new $ldr();
+		$ci->input = new Mock_Core_Input(NULL, NULL);
+
+		// Make sure string helper is available
+		$this->ci_vfs_clone('system/helpers/string_helper.php');
 
 		// Attach session instance locally
 		$config = array(
diff --git a/tests/codeigniter/libraries/Table_test.php b/tests/codeigniter/libraries/Table_test.php
index edfc83d..ce04b6a 100644
--- a/tests/codeigniter/libraries/Table_test.php
+++ b/tests/codeigniter/libraries/Table_test.php
@@ -4,12 +4,8 @@
 
 	public function set_up()
 	{
-		$obj = new stdClass;
-		$obj->table = new Mock_Libraries_Table();
-
-		$this->ci_instance($obj);
-
-		$this->table = $obj->table;
+		$this->table = new Mock_Libraries_Table();
+		$this->ci_instance_var('table', $this->table);
 	}
 
 	// Setter Methods
diff --git a/tests/codeigniter/libraries/Typography_test.php b/tests/codeigniter/libraries/Typography_test.php
index eb6dacb..5dba062 100644
--- a/tests/codeigniter/libraries/Typography_test.php
+++ b/tests/codeigniter/libraries/Typography_test.php
@@ -4,12 +4,8 @@
 
 	public function set_up()
 	{
-		$obj = new stdClass;
-		$obj->type = new Mock_Libraries_Typography();
-
-		$this->ci_instance($obj);
-
-		$this->type = $obj->type;
+		$this->type = new Mock_Libraries_Typography();
+		$this->ci_instance('type', $this->type);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/tests/codeigniter/libraries/Upload_test.php b/tests/codeigniter/libraries/Upload_test.php
index d79a3ff..8279427 100644
--- a/tests/codeigniter/libraries/Upload_test.php
+++ b/tests/codeigniter/libraries/Upload_test.php
@@ -4,18 +4,11 @@
 
 	function set_up()
 	{
-		$obj = new stdClass;
-		$obj->upload = new Mock_Libraries_Upload();
-		$obj->security = new Mock_Core_Security();
-		$obj->lang = new Mock_Core_Lang();
-
-		$this->ci_instance($obj);
-		$this->upload = $obj->upload;
-
-		vfsStreamWrapper::register();
-		vfsStreamWrapper::setRoot(new vfsStreamDirectory('testDir'));
-
-		$this->_test_dir = vfsStreamWrapper::getRoot();
+		$ci = $this->ci_instance();
+		$ci->upload = new Mock_Libraries_Upload();
+		$ci->security = new Mock_Core_Security();
+		$ci->lang = new Mock_Core_Lang();
+		$this->upload = $ci->upload;
 	}
 
 	function test_do_upload() 
@@ -64,11 +57,15 @@
 
 	function test_set_filename()
 	{
-		$file1 = vfsStream::newFile('hello-world.txt')->withContent('Hello world.')->at($this->_test_dir);
+		$dir = 'uploads';
+		$isnew = 'helloworld.txt';
+		$exists = 'hello-world.txt';
+		$this->ci_vfs_create($exists, 'Hello world.', $this->ci_app_root, $dir);
+		$path = $this->ci_vfs_path($dir.'/', APPPATH);
 		$this->upload->file_ext = '.txt';
 
-		$this->assertEquals('helloworld.txt', $this->upload->set_filename(vfsStream::url('testDir').'/', 'helloworld.txt'));
-		$this->assertEquals('hello-world1.txt', $this->upload->set_filename(vfsStream::url('testDir').'/', 'hello-world.txt'));
+		$this->assertEquals($isnew, $this->upload->set_filename($path, $isnew));
+		$this->assertEquals('hello-world1.txt', $this->upload->set_filename($path, $exists));
 	}
 
 	function test_set_max_filesize()
@@ -107,7 +104,7 @@
 	function test_set_image_properties()
 	{
 		$this->upload->file_type = 'image/gif';
-		$this->upload->file_temp = 'tests/mocks/uploads/ci_logo.gif';
+		$this->upload->file_temp = realpath(PROJECT_BASE.'tests/mocks/uploads/ci_logo.gif');
 
 		$props = array(
 			'image_width'	=>	170,
@@ -156,7 +153,7 @@
 		$this->assertTrue($this->upload->is_allowed_filetype(FALSE));
 		$this->assertTrue($this->upload->is_allowed_filetype(TRUE));
 
-		$this->upload->file_temp = 'tests/mocks/uploads/ci_logo.gif';
+		$this->upload->file_temp = realpath(PROJECT_BASE.'tests/mocks/uploads/ci_logo.gif');
 		$this->upload->file_ext = '.gif';
 		$this->upload->file_type = 'image/gif';
 		$this->assertTrue($this->upload->is_allowed_filetype());
@@ -179,7 +176,7 @@
 		$this->assertTrue($this->upload->is_allowed_dimensions());
 
 		$this->upload->file_type = 'image/gif';
-		$this->upload->file_temp = 'tests/mocks/uploads/ci_logo.gif';
+		$this->upload->file_temp = realpath(PROJECT_BASE.'tests/mocks/uploads/ci_logo.gif');
 
 		$this->upload->max_width = 10;		
 		$this->assertFalse($this->upload->is_allowed_dimensions());
@@ -197,7 +194,9 @@
 		$this->upload->upload_path = '';
 		$this->assertFalse($this->upload->validate_upload_path());
 
-		$this->upload->upload_path = vfsStream::url('testDir');
+		$dir = 'uploads';
+		$this->ci_vfs_mkdir($dir);
+		$this->upload->upload_path = $this->ci_vfs_path($dir);
 		$this->assertTrue($this->upload->validate_upload_path());
 	}
 
@@ -222,20 +221,24 @@
 
 	function test_do_xss_clean()
 	{
-		$file1 = vfsStream::newFile('file1.txt')->withContent('The billy goat was waiting for them.')->at($this->_test_dir);
-		$file2 = vfsStream::newFile('file2.txt')->at($this->_test_dir);
-		$file3 = vfsStream::newFile('file3.txt')->withContent('<script type="text/javascript">alert("Boo! said the billy goat")</script>')->at($this->_test_dir);
+		$dir = 'uploads';
+		$file1 = 'file1.txt';
+		$file2 = 'file2.txt';
+		$file3 = 'file3.txt';
+		$this->ci_vfs_create($file1, 'The billy goat was waiting for them.', $this->ci_vfs_root, $dir);
+		$this->ci_vfs_create($file2, '', $this->ci_vfs_root, $dir);
+		$this->ci_vfs_create($file3, '<script type="text/javascript">alert("Boo! said the billy goat")</script>', $this->ci_vfs_root, $dir);
 
-		$this->upload->file_temp = vfsStream::url('file1.txt');
+		$this->upload->file_temp = $this->ci_vfs_path($file1, $dir);
 		$this->assertTrue($this->upload->do_xss_clean());
 
-		$this->upload->file_temp = vfsStream::url('file2.txt');
+		$this->upload->file_temp = $this->ci_vfs_path($file2, $dir);
 		$this->assertFalse($this->upload->do_xss_clean());
 
-		$this->upload->file_temp = vfsStream::url('file3.txt');
+		$this->upload->file_temp = $this->ci_vfs_path($file3, $dir);
 		$this->assertFalse($this->upload->do_xss_clean());
 
-		$this->upload->file_temp = 'tests/mocks/uploads/ci_logo.gif';
+		$this->upload->file_temp = realpath(PROJECT_BASE.'tests/mocks/uploads/ci_logo.gif');
 		$this->assertTrue($this->upload->do_xss_clean());
 	}
 
diff --git a/tests/codeigniter/libraries/Useragent_test.php b/tests/codeigniter/libraries/Useragent_test.php
index 89383f8..e372655 100644
--- a/tests/codeigniter/libraries/Useragent_test.php
+++ b/tests/codeigniter/libraries/Useragent_test.php
@@ -10,12 +10,11 @@
 		// set a baseline user agent
 		$_SERVER['HTTP_USER_AGENT'] = $this->_user_agent;
 
-		$obj = new stdClass;
-		$obj->agent = new Mock_Libraries_UserAgent();
+		$this->ci_vfs_clone('application/config/user_agents.php');
 
-		$this->ci_instance($obj);
+		$this->agent = new Mock_Libraries_UserAgent();
 
-		$this->agent = $obj->agent;
+		$this->ci_instance_var('agent', $this->agent);
 	}
 
 	// --------------------------------------------------------------------
diff --git a/tests/mocks/autoloader.php b/tests/mocks/autoloader.php
index 88d016b..431c310 100644
--- a/tests/mocks/autoloader.php
+++ b/tests/mocks/autoloader.php
@@ -48,32 +48,32 @@
 
 		if (in_array($subclass, $ci_core))
 		{
-			$dir = BASEPATH.'core'.DIRECTORY_SEPARATOR;
+			$dir = SYSTEM_PATH.'core'.DIRECTORY_SEPARATOR;
 			$class = $subclass;
 		}
 		elseif (in_array($subclass, $ci_libraries))
 		{
-			$dir = BASEPATH.'libraries'.DIRECTORY_SEPARATOR;
+			$dir = SYSTEM_PATH.'libraries'.DIRECTORY_SEPARATOR;
 			$class = ($subclass === 'Driver_Library') ? 'Driver' : $subclass;
 		}
 		elseif (in_array($subclass, $ci_drivers))
 		{
-			$dir = BASEPATH.'libraries'.DIRECTORY_SEPARATOR.$subclass.DIRECTORY_SEPARATOR;
+			$dir = SYSTEM_PATH.'libraries'.DIRECTORY_SEPARATOR.$subclass.DIRECTORY_SEPARATOR;
 			$class = $subclass;
 		}
 		elseif (in_array(($parent = strtok($subclass, '_')), $ci_drivers)) {
-			$dir = BASEPATH.'libraries'.DIRECTORY_SEPARATOR.$parent.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
+			$dir = SYSTEM_PATH.'libraries'.DIRECTORY_SEPARATOR.$parent.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
 			$class = $subclass;
 		}
 		elseif (preg_match('/^CI_DB_(.+)_(driver|forge|result|utility)$/', $class, $m) && count($m) === 3)
 		{
-			$driver_path = BASEPATH.'database'.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
+			$driver_path = SYSTEM_PATH.'database'.DIRECTORY_SEPARATOR.'drivers'.DIRECTORY_SEPARATOR;
 			$dir = $driver_path.$m[1].DIRECTORY_SEPARATOR;
 			$file = $dir.$m[1].'_'.$m[2].'.php';
 		}
 		elseif (strpos($class, 'CI_DB') === 0)
 		{
-			$dir = BASEPATH.'database'.DIRECTORY_SEPARATOR;
+			$dir = SYSTEM_PATH.'database'.DIRECTORY_SEPARATOR;
 			$file = $dir.str_replace(array('CI_DB','active_record'), array('DB', 'active_rec'), $subclass).'.php';
 		}
 		else
diff --git a/tests/mocks/ci_testcase.php b/tests/mocks/ci_testcase.php
index eda9e1b..980e912 100644
--- a/tests/mocks/ci_testcase.php
+++ b/tests/mocks/ci_testcase.php
@@ -2,7 +2,9 @@
 
 class CI_TestCase extends PHPUnit_Framework_TestCase {
 
-	protected $ci_config;
+	public $ci_vfs_root;
+	public $ci_app_root;
+	public $ci_base_root;
 	protected $ci_instance;
 	protected static $ci_test_instance;
 
@@ -25,13 +27,18 @@
 	public function __construct()
 	{
 		parent::__construct();
-		$this->ci_config = array();
+		$this->ci_instance = new StdClass();
 	}
 
 	// --------------------------------------------------------------------
 
 	public function setUp()
 	{
+		// Setup VFS with base directories
+		$this->ci_vfs_root = vfsStream::setup();
+		$this->ci_app_root = vfsStream::newDirectory('application')->at($this->ci_vfs_root);
+		$this->ci_base_root = vfsStream::newDirectory('system')->at($this->ci_vfs_root);
+
 		if (method_exists($this, 'set_up'))
 		{
 			$this->set_up();
@@ -57,15 +64,27 @@
 
 	// --------------------------------------------------------------------
 
-	public function ci_set_config($key, $val = '')
+	public function ci_set_config($key = '', $val = '')
 	{
+		// Add test config
+		if ( ! isset($this->ci_instance->config))
+		{
+			$this->ci_instance->config = new CI_TestConfig();
+		}
+
+		// Empty key means just do setup above
+		if ($key === '')
+		{
+			return;
+		}
+
 		if (is_array($key))
 		{
-			$this->ci_config = $key;
+			$this->ci_instance->config->config = $key;
 		}
 		else
 		{
-			$this->ci_config[$key] = $val;
+			$this->ci_instance->config->config[$key] = $val;
 		}
 	}
 
@@ -73,7 +92,7 @@
 
 	public function ci_get_config()
 	{
-		return $this->ci_config;
+		return isset($this->ci_instance->config) ? $this->ci_instance->config->config : array();
 	}
 
 	// --------------------------------------------------------------------
@@ -132,7 +151,7 @@
 
 		if ( ! class_exists('CI_'.$class_name))
 		{
-			require_once BASEPATH.'core/'.$class_name.'.php';
+			require_once SYSTEM_PATH.'core/'.$class_name.'.php';
 		}
 
 		$GLOBALS[strtoupper($global_name)] = 'CI_'.$class_name;
@@ -148,6 +167,155 @@
 		$orig = $obj;
 	}
 
+	/**
+	 * Create VFS directory
+	 *
+	 * @param	string	Directory name
+	 * @param	object	Optional root to create in
+	 * @return	object	New directory object
+	 */
+	public function ci_vfs_mkdir($name, $root = NULL)
+	{
+		// Check for root
+		if ( ! $root)
+		{
+			$root = $this->ci_vfs_root;
+		}
+
+		// Return new directory object
+		return vfsStream::newDirectory($name)->at($root);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Create VFS content
+	 *
+	 * @param	string	File name
+	 * @param	string	File content
+	 * @param	object	VFS directory object
+	 * @param	mixed	Optional subdirectory path or array of subs
+	 * @return	void
+	 */
+	public function ci_vfs_create($file, $content = '', $root = NULL, $path = NULL)
+	{
+		// Check for array
+		if (is_array($file))
+		{
+			foreach ($file as $name => $content)
+			{
+				$this->ci_vfs_create($name, $content, $root, $path);
+			}
+			return;
+		}
+
+		// Assert .php extension if none given
+		if (pathinfo($file, PATHINFO_EXTENSION) == '')
+		{
+			$file .= '.php';
+		}
+
+		// Build content
+		$tree = array($file => $content);
+
+		// Check for path
+		$subs = array();
+		if ($path)
+		{
+			// Explode if not array
+			$subs = is_array($path) ? $path : explode('/', trim($path, '/'));
+		}
+
+		// Check for root
+		if ( ! $root)
+		{
+			// Use base VFS root
+			$root = $this->ci_vfs_root;
+		}
+
+		// Handle subdirectories
+		while (($dir = array_shift($subs)))
+		{
+			// See if subdir exists under current root
+			$dir_root = $root->getChild($dir);
+			if ($dir_root)
+			{
+			   	// Yes - recurse into subdir
+				$root = $dir_root;
+			}
+			else
+			{
+				// No - put subdirectory back and quit
+				array_unshift($subs, $dir);
+				break;
+			}
+		}
+
+		// Create any remaining subdirectories
+		if ($subs)
+		{
+			foreach (array_reverse($subs) as $dir)
+			{
+				// Wrap content in subdirectory for creation
+				$tree = array($dir => $tree);
+			}
+		}
+
+		// Create tree
+		vfsStream::create($tree, $root);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Clone a real file into VFS
+	 *
+	 * @param	string	Path from base directory
+	 * @return	bool	TRUE on success, otherwise FALSE
+	 */
+	public function ci_vfs_clone($path)
+	{
+		// Get real file contents
+		$content = file_get_contents(PROJECT_BASE.$path);
+		if ($content === FALSE)
+		{
+			// Couldn't find file to clone
+			return FALSE;
+		}
+
+		$this->ci_vfs_create(basename($path), $content, NULL, dirname($path));
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Helper to get a VFS URL path
+	 *
+	 * @param	string	Path
+	 * @param	string	Optional base path
+	 * @return	string	Path URL
+	 */
+	public function ci_vfs_path($path, $base = '')
+	{
+		// Check for base path
+		if ($base)
+		{
+			// Prepend to path
+			$path = rtrim($base, '/').'/'.ltrim($path, '/');
+
+			// Is it already in URL form?
+			if (strpos($path, '://') !== FALSE)
+			{
+				// Done - return path
+				return $path;
+			}
+		}
+
+		// Trim leading slash and return URL
+		return vfsStream::url(ltrim($path, '/'));
+	}
+
 	// --------------------------------------------------------------------
 	// Internals
 	// --------------------------------------------------------------------
@@ -171,7 +339,15 @@
 
 	public function helper($name)
 	{
-		require_once(BASEPATH.'helpers/'.$name.'_helper.php');
+		require_once(SYSTEM_PATH.'helpers/'.$name.'_helper.php');
+	}
+
+	// --------------------------------------------------------------------
+
+	public function lang($name)
+	{
+		require(SYSTEM_PATH.'language/english/'.$name.'_lang.php');
+		return $lang;
 	}
 
 	// --------------------------------------------------------------------
diff --git a/tests/mocks/ci_testconfig.php b/tests/mocks/ci_testconfig.php
new file mode 100644
index 0000000..eb318dd
--- /dev/null
+++ b/tests/mocks/ci_testconfig.php
@@ -0,0 +1,18 @@
+<?php
+
+class CI_TestConfig {
+
+	public $config = array();
+	public $_config_paths = array(APPPATH);
+
+	public function item($key)
+	{
+		return isset($this->config[$key]) ? $this->config[$key] : FALSE;
+	}
+
+	public function load($arg1, $arg2, $arg3)
+	{
+		return TRUE;
+	}
+
+}
diff --git a/tests/mocks/core/common.php b/tests/mocks/core/common.php
index a655ee1..b001074 100644
--- a/tests/mocks/core/common.php
+++ b/tests/mocks/core/common.php
@@ -39,6 +39,30 @@
 	}
 }
 
+if ( ! function_exists('get_mimes'))
+{
+	/**
+	 * Returns the MIME types array from config/mimes.php
+	 *
+	 * @return	array
+	 */
+	function &get_mimes()
+	{
+		static $_mimes = array();
+
+		if (empty($_mimes))
+		{
+			$path = realpath(PROJECT_BASE.'application/config/mimes.php');
+			if (is_file($path))
+			{
+				$_mimes = include($path);
+			}
+		}
+
+		return $_mimes;
+	}
+}
+
 // --------------------------------------------------------------------
 
 if ( ! function_exists('load_class'))
@@ -166,4 +190,4 @@
 	{
 		return TRUE;
 	}
-}
\ No newline at end of file
+}
diff --git a/tests/mocks/core/loader.php b/tests/mocks/core/loader.php
index 53d88d5..7ea4da3 100644
--- a/tests/mocks/core/loader.php
+++ b/tests/mocks/core/loader.php
@@ -3,29 +3,11 @@
 class Mock_Core_Loader extends CI_Loader {
 
 	/**
-	 * Since we use paths to load up models, views, etc, we need the ability to
-	 * mock up the file system so when core tests are run, we aren't mucking
-	 * in the application directory.  this will give finer grained control over
-	 * these tests.  So yeah, while this looks odd, I need to overwrite protected
-	 * class vars in the loader.  So here we go...
-	 *
-	 * @covers CI_Loader::__construct()
+	 * Give public access to _ci_autoloader for testing
 	 */
-	public function __construct()
+	public function autoload()
 	{
-		vfsStreamWrapper::register();
-		vfsStreamWrapper::setRoot(new vfsStreamDirectory('application'));
-
-		$this->models_dir 	= vfsStream::newDirectory('models')->at(vfsStreamWrapper::getRoot());
-		$this->libs_dir 	= vfsStream::newDirectory('libraries')->at(vfsStreamWrapper::getRoot());
-		$this->helpers_dir 	= vfsStream::newDirectory('helpers')->at(vfsStreamWrapper::getRoot());
-		$this->views_dir 	= vfsStream::newDirectory('views')->at(vfsStreamWrapper::getRoot());
-
-		$this->_ci_ob_level  		= ob_get_level();
-		$this->_ci_library_paths	= array(vfsStream::url('application').'/', BASEPATH);
-		$this->_ci_helper_paths 	= array(vfsStream::url('application').'/', BASEPATH);
-		$this->_ci_model_paths 		= array(vfsStream::url('application').'/');
-		$this->_ci_view_paths 		= array(vfsStream::url('application').'/views/' => TRUE);
+		$this->_ci_autoloader();
 	}
 
-}
\ No newline at end of file
+}