public final short readShort() throws IOException {
        if (input instanceof RandomAccessFile) {
            return ((RandomAccessFile) input).readShort();
        } else if (input instanceof DataInputStream) {
            return ((DataInputStream) input).readShort();
        } else {
            throw new UnsupportedOperationException("Unknown Hollow Blob Input type");
        }
    }
@Test
    public void testReadShort() throws IOException {
        HollowBlobInput inStream = HollowBlobInput.modeBasedSelector(MemoryMode.ON_HEAP, mockBlob);
        assertEquals(1, inStream.readShort()); // first short is 1
        assertEquals(1, inStream.readShort()); // second short is 1

        HollowBlobInput inBuffer = HollowBlobInput.modeBasedSelector(MemoryMode.SHARED_MEMORY_LAZY, mockBlob);
        assertEquals(1, inBuffer.readShort()); // first short is 1
        assertEquals(1, inBuffer.readShort()); // second short is 1
    }