### Question:
NullPrefixer implements Prefixer { @Override public int getPackedLength() { return 0; } 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 testGetPackedLength() throws Throwable { int result = NullPrefixer.INSTANCE.getPackedLength(); assertEquals(0, result, "result"); }