diff --git a/lib/Cake/Test/Case/TestSuite/CakeTestCaseTest.php b/lib/Cake/Test/Case/TestSuite/CakeTestCaseTest.php
index da97150c3..d7b62e190 100644
--- a/lib/Cake/Test/Case/TestSuite/CakeTestCaseTest.php
+++ b/lib/Cake/Test/Case/TestSuite/CakeTestCaseTest.php
@@ -39,6 +39,22 @@ class SecondaryPost extends Model {
 
 }
 
+/**
+ * ConstructorPost test stub.
+ */
+class ConstructorPost extends Model {
+
+/**
+ * @var string
+ */
+	public $useTable = 'posts';
+
+	public function __construct($id = false, $table = null, $ds = null) {
+		parent::__construct($id, $table, $ds);
+		$this->getDataSource()->cacheMethods = false;
+	}
+}
+
 /**
  * CakeTestCaseTest
  *
@@ -435,6 +451,16 @@ class CakeTestCaseTest extends CakeTestCase {
 		ConnectionManager::drop('test_secondary');
 	}
 
+/**
+ * Test getMockForModel when the model accesses the datasource in the constructor.
+ *
+ * @return void
+ */
+	public function testGetMockForModelConstructorDatasource() {
+		$post = $this->getMockForModel('ConstructorPost', array('save'), array('ds' => 'test'));
+		$this->assertEquals('test', $post->useDbConfig);
+	}
+
 /**
  * test getMockForModel() with plugin models
  *
diff --git a/lib/Cake/TestSuite/CakeTestCase.php b/lib/Cake/TestSuite/CakeTestCase.php
index c375717fe..ab04db6a7 100644
--- a/lib/Cake/TestSuite/CakeTestCase.php
+++ b/lib/Cake/TestSuite/CakeTestCase.php
@@ -718,13 +718,13 @@ abstract class CakeTestCase extends PHPUnit_Framework_TestCase {
  * @return Model
  */
 	public function getMockForModel($model, $methods = array(), $config = array()) {
-		$config += ClassRegistry::config('Model');
+		$defaults = ClassRegistry::config('Model');
+		unset($defaults['ds']);
 
 		list($plugin, $name) = pluginSplit($model, true);
 		App::uses($name, $plugin . 'Model');
 
-		$config = array_merge((array)$config, array('name' => $name));
-		unset($config['ds']);
+		$config = array_merge($defaults, (array)$config, array('name' => $name));
 
 		if (!class_exists($name)) {
 			throw new MissingModelException(array($model));