### Question:
OxmArpSpaSerializer extends AbstractOxmIpv4AddressSerializer { @Override protected int getOxmFieldCode() { return OxmMatchConstants.ARP_SPA; }  @Override void serialize(final MatchEntry entry, final ByteBuf outBuffer);  }### Answer:
@Test public void getOxmFieldCode() { assertEquals("Wrong oxm-class", OxmMatchConstants.ARP_SPA, serializer.getOxmFieldCode()); }