Adding wrapper for assertIsA() assertion in simpletest.

cake/tests/lib/cake_test_case.php

@@ -477,10 +477,22 @@ protected function expectException($name = 'Exception', $message = '') {
 * @param string $message the text to display if the assertion is not correct
 * @return void
 */
-	protected function assertReference(&$first,  &$second, $message = '') {
+	protected function assertReference(&$first, &$second, $message = '') {
 		return $this->assertSame($first, $second, $message);
 	}
 
+/**
+ * Compatibility wrapper for assertIsA
+ *
+ * @param string $object 
+ * @param string $type 
+ * @param string $message 
+ * @return void
+ */
+	protected function assertIsA($object, $type, $message = '') {
+		return $this->assertType($type, $object, $message);
+	}
+
 /**
 * Compatibility function to test if value is between an acceptable range
 * @param mixed $value