### Question:
PutOverlayOp extends Op { @Override public byte[] encode() throws IOException { ByteArrayOutputStream os = new ByteArrayOutputStream(); try (DataOutputStream dos = new DataOutputStream(os)) { dos.writeByte(Op.PUT_OVERLAY); dos.writeLong(variantSpan.start); dos.writeLong(variantSpan.width); dos.writeInt(linkTypes.size()); for (Integer i : linkTypes) { dos.writeInt(i); } } os.flush(); return os.toByteArray(); } PutOverlayOp(DataInputStream dis);  PutOverlayOp(VariantSpan variantSpan, Set<Integer> linkTypes); @Override byte[] encode(); @Override boolean equals(Object obj); @Override int hashCode(); final Set<Integer> linkTypes; final VariantSpan variantSpan; }### Answer:
@Test public void encodeDecode() throws Exception { PutOverlayOp op = new PutOverlayOp(new VariantSpan(100, 1), Sets.newSet(10, 5)); byte[] data = op.encode(); DataInputStream dis = new DataInputStream(new ByteArrayInputStream(data)); assertEquals(Op.PUT_OVERLAY, dis.readByte()); PutOverlayOp decoded = new PutOverlayOp(dis); assertEquals(op, decoded); }