### Question:
VerticalAxisImpl extends ReferenceableAxisImpl implements VerticalAxis { @Override public VerticalCrs getVerticalCrs() { return vCrs; } VerticalAxisImpl(String axisName, List<Double> values, VerticalCrs vCrs); @Override VerticalCrs getVerticalCrs(); @Override Extent<Double> getExtent(); @Override int hashCode(); @Override boolean equals(Object obj);  }### Answer:
@Test public void testGetMethods() { assertEquals(height, vAxis.getVerticalCrs()); Extent<Double> heightExtent = vAxis.getCoordinateExtent(); Double extentLow = heightValues.get(0) - heightStep / 2; Double extentHigh = heightValues.get(numberOfHeightValues) + heightStep / 2; Extent<Double> expectedHeightExtent = Extents.newExtent(extentLow, extentHigh); assertEquals(expectedHeightExtent, heightExtent); Array<Extent<Double>> heights = vAxis.getDomainObjects(); int heightCounter = 0; for (Extent<Double> hExtent : heights) { expectedHeightExtent = Extents.newExtent(extentLow + heightCounter * heightStep, extentLow + (++heightCounter) * heightStep); assertEquals(expectedHeightExtent, hExtent); } int expectedIndex = 4; Double fifthHeight = vAxis.getCoordinateValue(expectedIndex); assertEquals(heightValues.get(expectedIndex), fifthHeight); Extent<Double> expectedFifthHeightBound = Extents.newExtent(fifthHeight - heightStep / 2, fifthHeight + heightStep / 2); assertEquals(expectedFifthHeightBound, vAxis.getCoordinateBounds(expectedIndex)); assertEquals(heightValues, vAxis.getCoordinateValues()); assertEquals(vAxisName, vAxis.getName()); }