</section>
            </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'