+/**
+ * @covers Preprocessor
+ *
+ * @covers Preprocessor_DOM
+ * @covers PPDStack
+ * @covers PPDStackElement
+ * @covers PPDPart
+ * @covers PPFrame_DOM
+ * @covers PPTemplateFrame_DOM
+ * @covers PPCustomFrame_DOM
+ * @covers PPNode_DOM
+ *
+ * @covers Preprocessor_Hash
+ * @covers PPDStack_Hash
+ * @covers PPDStackElement_Hash
+ * @covers PPDPart_Hash
+ * @covers PPFrame_Hash
+ * @covers PPTemplateFrame_Hash
+ * @covers PPCustomFrame_Hash
+ * @covers PPNode_Hash_Tree
+ * @covers PPNode_Hash_Text
+ * @covers PPNode_Hash_Array
+ * @covers PPNode_Hash_Attr
+ */