+ return is_object( $obj ) && !$obj instanceof StubObject;
+ }
+
+ /**
+ * Unstubs an object, if it is a stub object. Can be used to break a
+ * infinite loop when unstubbing an object or to avoid reference parameter
+ * breakage.
+ *
+ * @param $obj Object to check.
+ * @return void
+ */
+ static function unstub( $obj ) {
+ if ( $obj instanceof StubObject ) {
+ $obj->_unstub( 'unstub', 3 );
+ }