DomBuilder builder = new DomBuilder(sibling.ownerDocument, null)
        cl.delegate = builder
        cl.call()
        def parent = sibling.parentNode
        def next = sibling.nextSibling
        builder.elements.each { element ->
            parent.insertBefore(element, next)
        }
        return builder.elements.size() == 1 ? builder.elements[0] : builder.elements
    }

            def doc = new ClassDoc('org.gradle.Class', content, document, classMetaData, null)
            doc.superClass = superDoc
            doc.interfaces << superType1
            doc.interfaces << superType2
            builder.build(doc)
            return doc
        }

        then:
        doc.classProperties.size() == 5
        doc.classProperties[0].name == 'a'
        doc.classProperties[1].name == 'b'

            </section>
        ''')

        when:
        ClassDoc doc = withCategories {
            def doc = new ClassDoc('org.gradle.Class', content, document, classMetaData, extensionMetaData)
            builder.build(doc)
            doc.mergeContent()
        }

        then:
        doc.classExtensions.size() == 2

        doc.classExtensions[0].pluginId == 'a'

        format(nodes, true)
    }

    def format(Iterable<? extends Node> nodes, boolean prettyPrint = false) {
        StringBuilder builder = new StringBuilder()
        nodes.each { node ->
            format(node, builder, 0, prettyPrint, prettyPrint)
        }
        return builder.toString()
    }

    def format(Node node, Appendable target, int depth, boolean prettyPrint, boolean indentSelf) {

            doc.superClass = superClass
            doc.interfaces << superType1
            doc.interfaces << superType2
            builder.build(doc)
            doc
        }

        then:
        doc.classMethods.size() == 6

        doc.classMethods[0].name == 'a'
        doc.classMethods[1].name == 'b'
        doc.classMethods[2].name == 'b'