### Question:
ByteOption extends ValueOption<ByteOption> { @SuppressWarnings("deprecation") @Override public int restore(byte[] bytes, int offset, int limit) throws IOException { if (limit - offset == 0) { throw new IOException(MessageFormat.format( "Cannot restore a byte field ({0})", "invalid length")); } if (bytes[offset + 0] == 0) { setNull(); return 1; } else if (limit - offset >= 1 + 1) { modify(bytes[offset + 1]); return 2; } else { throw new IOException(MessageFormat.format( "Cannot restore a byte field ({0})", "invalid length")); } } ByteOption();  ByteOption(byte value); byte get(); byte or(byte alternate); @Deprecated ByteOption modify(byte newValue); @Override @Deprecated void copyFrom(ByteOption optionOrNull); @Override int hashCode(); @Override boolean equals(Object obj); @Override int compareTo(WritableRawComparable o); boolean has(int other); @Override String toString(); @Override void write(DataOutput out); @SuppressWarnings("deprecation") @Override void readFields(DataInput in); @SuppressWarnings("deprecation") @Override int restore(byte[] bytes, int offset, int limit); @Override int getSizeInBytes(byte[] buf, int offset); @Override int compareInBytes(byte[] b1, int o1, byte[] b2, int o2); static int getBytesLength(byte[] bytes, int offset, int length); static int compareBytes(
            byte[] b1, int s1, int l1,
            byte[] b2, int s2, int l2);  }### Answer:
@Test public void writeNull() { ByteOption option = new ByteOption(); ByteOption restored = restore(option); assertThat(restored.isNull(), is(true)); }