### Question:
RpcAdminData { public void addAdditionalRpcServiceId(String id) { if (id != null && id.length() > 0) { this.additionalRpcServiceIds.add(id); } } RpcAdminData();  RpcAdminData(Set<String> additionalRpcServiceIds); Set<String> getAdditionalRpcServiceIds(); void setAdditionalRpcServiceIds(Set<String> ids); void addAdditionalRpcServiceId(String id); void removeAdditionalRpcServiceId(String id); @Override boolean equals(Object obj); @Override int hashCode();  }### Answer:
@Test public void testAddAdditionalRpcServiceId() { assertEquals(populatedIds, populated.getAdditionalRpcServiceIds()); Set<String> newIds = Sets.newHashSet(populatedIds); populated.addAdditionalRpcServiceId("rpc3"); populated.addAdditionalRpcServiceId(null); newIds.add("rpc3"); assertEquals(newIds, populated.getAdditionalRpcServiceIds()); Set<String> emptyRpcIds = Sets.newHashSet(); assertEquals(emptyRpcIds, empty.getAdditionalRpcServiceIds()); empty.addAdditionalRpcServiceId("rpc4"); empty.addAdditionalRpcServiceId(null); emptyRpcIds.add("rpc4"); assertEquals(emptyRpcIds, empty.getAdditionalRpcServiceIds()); emptyRpcIds = Sets.newHashSet(); assertEquals(emptyRpcIds, nullData.getAdditionalRpcServiceIds()); nullData.addAdditionalRpcServiceId("rpc4"); nullData.addAdditionalRpcServiceId(null); emptyRpcIds.add("rpc4"); assertEquals(emptyRpcIds, nullData.getAdditionalRpcServiceIds()); }