[3919] Passed objects by reference

src/bin/dhcp6/tests/dhcp6_srv_unittest.cc

@@ -2086,7 +2086,7 @@ TEST_F(Dhcpv6SrvTest, relayOverrideAndClientClass) {
 /// @param codes a vector of option codes to be created
 /// @param payload specified payload (0 = fill payload with repeating option code)
 /// @return RSOO with nested options
-OptionPtr createRSOO(const std::vector<uint16_t> codes, uint8_t payload = 0) {
+OptionPtr createRSOO(const std::vector<uint16_t>& codes, uint8_t payload = 0) {
     OptionDefinitionPtr def = LibDHCP::getOptionDef(Option::V6, D6O_RSOO);
     if (!def) {
         isc_throw(BadValue, "Can't find RSOO definition");

src/bin/dhcp6/tests/fqdn_unittest.cc

@@ -389,7 +389,7 @@ public:
                             const std::string& exp_hostname,
                             const uint8_t client_flags =
                                 Option6ClientFqdn::FLAG_S,
-                            const IOAddress expected_address = IOAddress("2001:db8:1:1::dead:beef"),
+                            const IOAddress& expected_address = IOAddress("2001:db8:1:1::dead:beef"),
                             const bool include_oro = true) {
         // Create a message of a specified type, add server id and
         // FQDN option.