* </gmd:verticalElement>
*/
final VerticalExtent ve = getSingleton(extent.getVerticalElements());
assertEquals("minimumValue", 0.1, ve.getMinimumValue(), STRICT);
assertEquals("maximumValue", 10000, ve.getMaximumValue(), STRICT);
final VerticalCRS crs = ve.getVerticalCRS();
verifyIdentifiers("test1", crs);
assertEquals("scope", "World", crs.getScope().toString());
final VerticalDatum datum = crs.getDatum();
verifyIdentifiers("test2", datum);
assertEquals("scope", "World", datum.getScope().toString());
assertEquals("vertDatumType", VerticalDatumType.DEPTH, datum.getVerticalDatumType()); // Inferred from the name.
final VerticalCS cs = crs.getCoordinateSystem();
verifyIdentifiers("test3", cs);
final CoordinateSystemAxis axis = cs.getAxis(0);
verifyIdentifiers("test4", axis);
assertEquals("axisAbbrev", "d", axis.getAbbreviation());
assertEquals("axisDirection", AxisDirection.DOWN, axis.getDirection());