EDIT

import java.util.stream.Collectors;

import eu.etaxonomy.dataportal.elements.DerivedUnitTree;

import eu.etaxonomy.dataportal.elements.DerivedUnitTreeNode;

import eu.etaxonomy.dataportal.elements.DetailsTable;

    List<DerivedUnitTree> duTrees;

        duTrees = p.getDataPortalContent().getElement().findElements(By.cssSelector(".derived-unit-tree")).stream()

                .map(el -> DerivedUnitTree.from(el))

                .collect(Collectors.toList());

    //@Test

        assertEquals(3, duTrees.size());

        BaseElement rootNodeHeader1 = duTrees.get(0).getRootNode().getHeader();

        assertEquals("(B SP-99999).", rootNodeHeader1.getText());

        BaseElement rootNodeHeader2 = duTrees.get(1).getRootNode().getHeader();

        assertEquals("Germany, Berlin, 2 Apr 1835.", rootNodeHeader2.getText());

        BaseElement rootNodeHeader3 = duTrees.get(2).getRootNode().getHeader();

        assertEquals("Germany, Berlin, alt. 165 m, 52°31'1.2\"N, 13°21'E (WGS84), 28 Mar 2016, Ehrenberg D047.", rootNodeHeader3.getText());

    //@Test

    public void testDerivationTree1() {

        DerivedUnitTree tree1 = duTrees.get(0);

        DerivedUnitTreeNode rootNode = tree1.getRootNode();

        DerivedUnitTreeNode subNode1 = rootNode.getSubNodes().get(0);

        DerivedUnitTreeNode subNode2 = rootNode.getSubNodes().get(1);

        DerivedUnitTreeNode subNode3 = rootNode.getSubNodes().get(2);

        assertEquals("(B SP-99999).", rootNode.getHeader().getText());

        assertEquals("(B B-923845).", subNode1.getHeader().getText());

        assertEquals("(B DNA-9098080).", subNode2.getHeader().getText());

        assertEquals("B_SP-99999.png", subNode3.getHeader().getText());

    }

    //@Test

    public void testDerivationTree2() {

        DerivedUnitTree tree2 = duTrees.get(1);

        DerivedUnitTreeNode rootNode = tree2.getRootNode();

        DerivedUnitTreeNode subNode1 = rootNode.getSubNodes().get(0);

        assertEquals("Germany, Berlin, 2 Apr 1835.", rootNode.getHeader().getText());

        assertEquals("BHUPM 671 (ECdraw671.jpg)", subNode1.getHeader().getText());

        // ---- root node

        rootNode.getHeader().getElement().click(); // make the  content visible

        LinkElement pageLink = rootNode.getHeader().getLinksInElement().get(0);

        assertTrue(pageLink.getUrl().endsWith("cdm_dataportal/occurrence/75b73483-7ee6-4c2c-8826-1e58a0ed18e0"));

        DetailsTable fieldUnitTable = rootNode.getDetailsTable(DetailsTable.tableClassAttrFrom("Field Unit"));

        assertEquals("Field Unit", fieldUnitTable.getHeaderText());

        assertEquals("field note 1", fieldUnitTable.getDetailsValueCellText("Field notes"));

        DetailsTable gatheringTable = rootNode.getDetailsTable(DetailsTable.tableClassAttrFrom("Gathering & Location"));

        assertEquals("Gathering & Location", gatheringTable.getHeaderText());

        assertEquals("Germany", gatheringTable.getDetailsValueCellText("Country"));

        assertEquals("Berlin", gatheringTable.getDetailsValueCellText("Locality"));

        assertEquals("1835-04-02", gatheringTable.getDetailsValueCellText("Date"));

        // TODO check all links

        // descriptionListContainer = new BaseElement(derivateTreeContainer);

        // assertEquals(7, descriptionListContainer.getLinksInElement().size()); // other links in the derivate tree are also found

        // ---- sub node 1

        subNode1.getHeader().getElement().click(); // make the  content visible

        pageLink = subNode1.getHeader().getLinksInElement().get(0);

        assertTrue(pageLink.getUrl().endsWith("cdm_dataportal/occurrence/eb729673-5206-49fb-b902-9214d8bdbb51"));

        assertEquals("Gathering in-situ", subNode1.getDerivationEvent());

        DetailsTable imageTable = subNode1.getDetailsTable(DetailsTable.tableClassAttrFrom("Still Image"));

        assertEquals("Still Image", imageTable.getHeaderText());

        assertEquals("Unpublished image", imageTable.getDetailsValueCellText("Kind of unit"));

        assertEquals("671", imageTable.getDetailsValueCellText("Accession number"));

        assertEquals("BHUPM", imageTable.getDetailsValueCellText("Collection"));

        DetailsTable typeDesignationsTable = subNode1.getDetailsTable(DetailsTable.tableClassAttrFrom("Type designations"));

                typeDesignationsTable.getBodyCellText(0, 0));

    public void testDerivationTree3() {

        DerivedUnitTree tree3 = duTrees.get(2);

        DerivedUnitTreeNode rootNode = tree3.getRootNode();

        DerivedUnitTreeNode subNode1 = rootNode.getSubNodes().get(0);

        DerivedUnitTreeNode subNode2 = rootNode.getSubNodes().get(1);

        assertEquals("Germany, Berlin, alt. 165 m, 52°31'1.2\"N, 13°21'E (WGS84), 28 Mar 2016, Ehrenberg D047.", rootNode.getHeader().getText());

        assertEquals("Germany, Berlin, alt. 165 m, 52°31'1.2\"N, 13°21'E (WGS84), 28 Mar 2016, Ehrenberg D047; D. Veloper (CEDiT 2017E68).", subNode1.getHeader().getText());

        assertEquals("Germany, Berlin, alt. 165 m, 52°31'1.2\"N, 13°21'E (WGS84), 28 Mar 2016, Ehrenberg D047 (M M-0289351).", subNode2.getHeader().getText());

        // --- Root note

        rootNode.getHeader().getElement().click(); // make the  content visible

        LinkElement pageLink = rootNode.getHeader().getLinksInElement().get(0);

        assertTrue(pageLink.getUrl().endsWith("/cdm_dataportal/occurrence/89d36e79-3e80-4468-986e-411ca391452e"));

        DetailsTable fieldUnitTable = rootNode.getDetailsTable(DetailsTable.tableClassAttrFrom("Field Unit"));

        assertEquals("Field Unit", fieldUnitTable.getHeaderText());

        assertEquals("D047", fieldUnitTable.getDetailsValueCellText("Collecting number"));

        DetailsTable gatheringTable = rootNode.getDetailsTable(DetailsTable.tableClassAttrFrom("Gathering & Location"));

        assertEquals("Gathering & Location", gatheringTable.getHeaderText());

        assertEquals("2016-03-28", gatheringTable.getDetailsValueCellText("Date"));

        assertEquals("Ehrenberg, C.G.", gatheringTable.getDetailsValueCellText("Collector"));

        assertEquals("Berlin", gatheringTable.getDetailsValueCellText("Locality"));

        assertEquals("Germany", gatheringTable.getDetailsValueCellText("Country"));

        assertEquals("52°31'1.2\"N, 13°21'E +/-20 m (WGS84)", gatheringTable.getDetailsValueCellText("Exact location"));

        assertEquals("165 m", gatheringTable.getDetailsValueCellText("Altitude"));

        //TODO test all links

        // assertEquals(17, descriptionListContainer.getLinksInElement().size()); // other links in the derivate tree are also found

        // link1 = descriptionListContainer.getLinksInElement().get(1);

        // --- node 1

        subNode1.getHeader().getElement().click();

        assertTrue(subNode1.getHeader().getLinksInElement().get(0).getUrl().endsWith("/cdm_dataportal/occurrence/8585081c-b73b-440b-b349-582845cf3fb4"));

        assertEquals("Gathering in-situ", subNode1.getDerivationEvent());

        DetailsTable preserverdSpecimenTable_1 = subNode1.getDetailsTable(DetailsTable.tableClassAttrFrom("Preserved Specimen"));

        assertEquals("Preserved Specimen", preserverdSpecimenTable_1.getHeaderText());

        assertEquals("Specimen", preserverdSpecimenTable_1.getDetailsValueCellText("Kind of unit"));

        assertEquals("2017E68", preserverdSpecimenTable_1.getDetailsValueCellText("Accession number"));

        assertEquals("http://testid.org/2017E68", preserverdSpecimenTable_1.getDetailsValueCellText("Preferred stable uri"));

        assertEquals("CEDiT at Botanic Garden and Botanical Museum Berlin-Dahlem (BGBM)", preserverdSpecimenTable_1.getDetailsValueCellText("Collection"));

        assertEquals("Glenodinium apiculatum", preserverdSpecimenTable_1.getDetailsValueCellText("Stored under"));

        assertEquals("D. Veloper", preserverdSpecimenTable_1.getDetailsValueCellText("Exsiccatum"));

        assertEquals("CE_2017E68", preserverdSpecimenTable_1.getDetailsValueCellText("Catalog number"));

        assertEquals("E2017E68", preserverdSpecimenTable_1.getDetailsValueCellText("Barcode"));

        DetailsTable typeDesignationsTable_1 = subNode1.getDetailsTable(DetailsTable.tableClassAttrFrom("Type designations"));

        assertEquals("Epitype (designated by Kretschmann, J., Žerdoner ?alasan, A. & Kusber, W.-H. 20171)",

                typeDesignationsTable_1.getBodyCellText(0, 0));

        DetailsTable identificationsTable_1 = subNode1.getDetailsTable(DetailsTable.tableClassAttrFrom("Identification"));

        assertEquals("Glenodinium apiculatum",

                identificationsTable_1.getBodyCellText(0, 0));

        // FIXME:

        // Link is missing!!!

        // specimenTypeDesignation_dd = dl2.getDescriptionGroups().get("Specimen type designations:").get(0);

        // specimenTypeDesignationLinks = specimenTypeDesignation_dd.getLinksInElement();

        // assertEquals("expecting one footnote key link", 1, specimenTypeDesignationLinks.size());

        subNode2.getHeader().getElement().click();

        assertTrue(subNode2.getHeader().getLinksInElement().get(0).getUrl().endsWith("/cdm_dataportal/occurrence/e86c5acd-de55-44af-99f7-484207657264"));

        assertEquals("Gathering in-situ", subNode2.getDerivationEvent());

        DetailsTable preserverdSpecimenTable_2 = subNode2.getDetailsTable(DetailsTable.tableClassAttrFrom("Preserved Specimen"));

        assertEquals("Preserved Specimen", preserverdSpecimenTable_2.getHeaderText());

        assertEquals("http://herbarium.bgbm.org/object/B400042045", preserverdSpecimenTable_2.getDetailsValueCellText("Preferred stable uri"));

        assertEquals("Specimen", preserverdSpecimenTable_2.getDetailsValueCellText("Kind of unit"));

        DetailsTable typeDesignationsTable_2 = subNode2.getDetailsTable(DetailsTable.tableClassAttrFrom("Type designations"));

        assertEquals("Isolectotype (designated by Kretschmann, J., Žerdoner ?alasan, A. & Kusber, W.-H. 20171)",

                typeDesignationsTable_2.getBodyCellText(0, 0));

        assertEquals("expecting one footnote key link", 1, typeDesignationsTable_2.getBodyCell(0, 0).getLinksInElement().size());