### Question:
NullPrefixer implements Prefixer { @Override public int decodeLength(byte[] b, int offset) { return -1; } private  NullPrefixer(); @Override void encodeLength(int length, byte[] b); @Override int decodeLength(byte[] b, int offset); @Override int getPackedLength(); static final NullPrefixer INSTANCE; }### Answer:
@Test public void testDecodeLength() throws Throwable { byte[] b = new byte[2]; int result = NullPrefixer.INSTANCE.decodeLength(b, 100); assertEquals(-1, result, "result"); }