[#248] template classes can add regular classes

32 files changed, 215 insertions, 168 deletions

diff --git a/src/bin/d2/parser_context.cc b/src/bin/d2/parser_context.cc
index 703460a6de..f27a628c6a 100644
--- a/src/bin/d2/parser_context.cc
+++ b/src/bin/d2/parser_context.cc
@@ -169,25 +169,25 @@ D2ParserContext::contextName()
     case TSIG_KEYS:
         return ("tsig-keys");
     case ALGORITHM:
-        return ("algorithm");
+        return("algorithm");
     case DIGEST_BITS:
-        return ("digest-bits");
+        return("digest-bits");
     case SECRET:
-        return ("secret");
+        return("secret");
     case FORWARD_DDNS:
-        return ("forward-ddns");
+        return("forward-ddns");
     case REVERSE_DDNS:
-        return ("reverse-ddns");
+        return("reverse-ddns");
     case DDNS_DOMAIN:
-        return ("ddns-domain");
+        return("ddns-domain");
     case DDNS_DOMAINS:
-        return ("ddns-domains");
+        return("ddns-domains");
     case DNS_SERVER:
-        return ("dns-server");
+        return("dns-server");
     case DNS_SERVERS:
-        return ("dns-servers");
+        return("dns-servers");
     case CONTROL_SOCKET:
-        return ("control-socket");
+        return("control-socket");
     case LOGGERS:
         return ("loggers");
     case OUTPUT_OPTIONS:
diff --git a/src/bin/dhcp4/dhcp4_lexer.ll b/src/bin/dhcp4/dhcp4_lexer.ll
index 1aebaf1551..ccd6a72530 100644
--- a/src/bin/dhcp4/dhcp4_lexer.ll
+++ b/src/bin/dhcp4/dhcp4_lexer.ll
@@ -1279,12 +1279,12 @@ ControlCharacterFill            [^"\\]|\\["\\/bfnrtu]
     }
 }
 
-\"template-class\" {
+\"template-test\" {
     switch(driver.ctx_) {
     case isc::dhcp::Parser4Context::CLIENT_CLASSES:
-        return isc::dhcp::Dhcp4Parser::make_TEMPLATE_CLASS(driver.loc_);
+        return isc::dhcp::Dhcp4Parser::make_TEMPLATE_TEST(driver.loc_);
     default:
-        return isc::dhcp::Dhcp4Parser::make_STRING("template-class", driver.loc_);
+        return isc::dhcp::Dhcp4Parser::make_STRING("template-test", driver.loc_);
     }
 }
 
diff --git a/src/bin/dhcp4/dhcp4_parser.yy b/src/bin/dhcp4/dhcp4_parser.yy
index 9783cc9d18..f5c04dc8ce 100644
--- a/src/bin/dhcp4/dhcp4_parser.yy
+++ b/src/bin/dhcp4/dhcp4_parser.yy
@@ -170,7 +170,7 @@ using namespace std;
   CLIENT_CLASSES "client-classes"
   REQUIRE_CLIENT_CLASSES "require-client-classes"
   TEST "test"
-  TEMPLATE_CLASS "template-class"
+  TEMPLATE_TEST "template-test"
   ONLY_IF_REQUIRED "only-if-required"
   CLIENT_CLASS "client-class"
 
@@ -2336,7 +2336,7 @@ not_empty_client_class_params: client_class_param
 
 client_class_param: client_class_name
                   | client_class_test
-                  | client_class_template_class
+                  | client_class_template_test
                   | only_if_required
                   | option_def_list
                   | option_data_list
@@ -2362,10 +2362,13 @@ client_class_test: TEST {
     ctx.leave();
 };
 
-client_class_template_class: TEMPLATE_CLASS COLON BOOLEAN {
-    ctx.unique("template-class", ctx.loc2pos(@1));
-    ElementPtr b(new BoolElement($3, ctx.loc2pos(@3)));
-    ctx.stack_.back()->set("template-class", b);
+client_class_template_test: TEMPLATE_TEST {
+    ctx.unique("template-test", ctx.loc2pos(@1));
+    ctx.enter(ctx.NO_KEYWORD);
+} COLON STRING {
+    ElementPtr template_test(new StringElement($4, ctx.loc2pos(@4)));
+    ctx.stack_.back()->set("template-test", template_test);
+    ctx.leave();
 };
 
 only_if_required: ONLY_IF_REQUIRED COLON BOOLEAN {
diff --git a/src/bin/dhcp4/dhcp4_srv.cc b/src/bin/dhcp4/dhcp4_srv.cc
index 017affde7f..df0b100047 100644
--- a/src/bin/dhcp4/dhcp4_srv.cc
+++ b/src/bin/dhcp4/dhcp4_srv.cc
@@ -250,7 +250,7 @@ Dhcpv4Exchange::Dhcpv4Exchange(const AllocEnginePtr& alloc_engine,
     // Perform second pass of classification.
     evaluateClasses(query, true);
 
-    const ClientClasses& classes = query_->getClassesAndSubClasses();
+    const ClientClasses& classes = query_->getClasses();
     if (!classes.empty()) {
         LOG_DEBUG(dhcp4_logger, DBG_DHCP4_BASIC, DHCP4_CLASS_ASSIGNED)
             .arg(query_->getLabel())
@@ -2489,7 +2489,7 @@ Dhcpv4Srv::assignLease(Dhcpv4Exchange& ex) {
 
         Lease4Ptr lease;
 
-        auto const& classes = query->getClassesAndSubClasses();
+        auto const& classes = query->getClasses();
 
         // We used to issue a separate query (two actually: one for client-id
         // and another one for hw-addr for) each subnet in the shared network.
diff --git a/src/bin/dhcp4/tests/config_parser_unittest.cc b/src/bin/dhcp4/tests/config_parser_unittest.cc
index a263daf940..f80a8d6d64 100644
--- a/src/bin/dhcp4/tests/config_parser_unittest.cc
+++ b/src/bin/dhcp4/tests/config_parser_unittest.cc
@@ -6103,11 +6103,11 @@ TEST_F(Dhcp4ParserTest, templateClientClassValidLifetime) {
         "       \"min-valid-lifetime\": 1000, \n"
         "       \"valid-lifetime\": 2000, \n"
         "       \"max-valid-lifetime\": 3000, \n"
-        "       \"template-class\": true, \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"two\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   } \n"
         "], \n"
         "\"subnet4\": [ {  \n"
diff --git a/src/bin/dhcp4/tests/fqdn_unittest.cc b/src/bin/dhcp4/tests/fqdn_unittest.cc
index 2caf0ec6dd..2a275c6041 100644
--- a/src/bin/dhcp4/tests/fqdn_unittest.cc
+++ b/src/bin/dhcp4/tests/fqdn_unittest.cc
@@ -398,7 +398,7 @@ public:
             return (DdnsParamsPtr(new DdnsParams()));
         }
 
-        return (CfgMgr::instance().getCurrentCfg()->getDdnsParams(subnet_));
+        return(CfgMgr::instance().getCurrentCfg()->getDdnsParams(subnet_));
     }
 
     // Create a lease to be used by various tests.
@@ -457,8 +457,8 @@ public:
     /// @return An std::string contained the generated FQDN.
     std::string generatedNameFromAddress(const IOAddress& addr,
                                          const bool trailing_dot = true) {
-        return (CfgMgr::instance().getD2ClientMgr()
-                .generateFqdn(addr, *getDdnsParams(), trailing_dot));
+        return(CfgMgr::instance().getD2ClientMgr()
+               .generateFqdn(addr, *getDdnsParams(), trailing_dot));
     }
 
     // Get the Client FQDN Option from the given message.
diff --git a/src/bin/dhcp4/tests/simple_parser4_unittest.cc b/src/bin/dhcp4/tests/simple_parser4_unittest.cc
index df104f8293..6ac157a99c 100644
--- a/src/bin/dhcp4/tests/simple_parser4_unittest.cc
+++ b/src/bin/dhcp4/tests/simple_parser4_unittest.cc
@@ -210,6 +210,6 @@ TEST_F(SimpleParser4Test, optionDefDefaults4) {
     checkBoolValue(def, "array", false);
 }
 
-}
-}
-}
+};
+};
+};
diff --git a/src/bin/dhcp6/dhcp6_lexer.ll b/src/bin/dhcp6/dhcp6_lexer.ll
index e9577eec15..6e6340a6fa 100644
--- a/src/bin/dhcp6/dhcp6_lexer.ll
+++ b/src/bin/dhcp6/dhcp6_lexer.ll
@@ -1611,12 +1611,12 @@ ControlCharacterFill            [^"\\]|\\["\\/bfnrtu]
     }
 }
 
-\"template-class\" {
+\"template-test\" {
     switch(driver.ctx_) {
     case isc::dhcp::Parser6Context::CLIENT_CLASSES:
-        return isc::dhcp::Dhcp6Parser::make_TEMPLATE_CLASS(driver.loc_);
+        return isc::dhcp::Dhcp6Parser::make_TEMPLATE_TEST(driver.loc_);
     default:
-        return isc::dhcp::Dhcp6Parser::make_STRING("template-class", driver.loc_);
+        return isc::dhcp::Dhcp6Parser::make_STRING("template-test", driver.loc_);
     }
 }
 
diff --git a/src/bin/dhcp6/dhcp6_parser.yy b/src/bin/dhcp6/dhcp6_parser.yy
index 23d12eb637..18e90b911d 100644
--- a/src/bin/dhcp6/dhcp6_parser.yy
+++ b/src/bin/dhcp6/dhcp6_parser.yy
@@ -168,7 +168,7 @@ using namespace std;
   CLIENT_CLASSES "client-classes"
   REQUIRE_CLIENT_CLASSES "require-client-classes"
   TEST "test"
-  TEMPLATE_CLASS "template-class"
+  TEMPLATE_TEST "template-test"
   ONLY_IF_REQUIRED "only-if-required"
   CLIENT_CLASS "client-class"
 
@@ -2408,7 +2408,7 @@ not_empty_client_class_params: client_class_param
 
 client_class_param: client_class_name
                   | client_class_test
-                  | client_class_template_class
+                  | client_class_template_test
                   | only_if_required
                   | option_data_list
                   | user_context
@@ -2433,10 +2433,13 @@ client_class_test: TEST {
     ctx.leave();
 };
 
-client_class_template_class: TEMPLATE_CLASS COLON BOOLEAN {
-    ctx.unique("template-class", ctx.loc2pos(@1));
-    ElementPtr b(new BoolElement($3, ctx.loc2pos(@3)));
-    ctx.stack_.back()->set("template-class", b);
+client_class_template_test: TEMPLATE_TEST {
+    ctx.unique("template-test", ctx.loc2pos(@1));
+    ctx.enter(ctx.NO_KEYWORD);
+} COLON STRING {
+    ElementPtr template_test(new StringElement($4, ctx.loc2pos(@4)));
+    ctx.stack_.back()->set("template-test", template_test);
+    ctx.leave();
 };
 
 only_if_required: ONLY_IF_REQUIRED COLON BOOLEAN {
diff --git a/src/bin/dhcp6/dhcp6_srv.cc b/src/bin/dhcp6/dhcp6_srv.cc
index 34f08986f6..dfad23ba04 100644
--- a/src/bin/dhcp6/dhcp6_srv.cc
+++ b/src/bin/dhcp6/dhcp6_srv.cc
@@ -569,7 +569,7 @@ Dhcpv6Srv::initContext(const Pkt6Ptr& pkt,
     // Perform second pass of classification.
     evaluateClasses(pkt, true);
 
-    const ClientClasses& classes = pkt->getClassesAndSubClasses();
+    const ClientClasses& classes = pkt->getClasses();
     if (!classes.empty()) {
         LOG_DEBUG(dhcp6_logger, DBG_DHCP6_BASIC, DHCP6_CLASS_ASSIGNED)
             .arg(pkt->getLabel())
@@ -4056,7 +4056,7 @@ Dhcpv6Srv::setReservedClientClasses(const Pkt6Ptr& pkt,
         }
     }
 
-    const ClientClasses& classes = pkt->getClassesAndSubClasses();
+    const ClientClasses& classes = pkt->getClasses();
     if (!classes.empty()) {
         LOG_DEBUG(dhcp6_logger, DBG_DHCP6_BASIC, DHCP6_CLASS_ASSIGNED)
             .arg(pkt->getLabel())
diff --git a/src/bin/dhcp6/tests/config_parser_unittest.cc b/src/bin/dhcp6/tests/config_parser_unittest.cc
index cc3c6a8989..33b64c02b4 100644
--- a/src/bin/dhcp6/tests/config_parser_unittest.cc
+++ b/src/bin/dhcp6/tests/config_parser_unittest.cc
@@ -8169,11 +8169,11 @@ TEST_F(Dhcp6ParserTest, templateClientClassValidPreferredLifetime) {
         "       \"min-preferred-lifetime\": 4000, \n"
         "       \"preferred-lifetime\": 5000, \n"
         "       \"max-preferred-lifetime\": 6000, \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"two\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   } \n"
         "], \n"
         "\"subnet6\": [ {  \n"
diff --git a/src/bin/dhcp6/tests/fqdn_unittest.cc b/src/bin/dhcp6/tests/fqdn_unittest.cc
index a26c0b7e8c..683a71cf62 100644
--- a/src/bin/dhcp6/tests/fqdn_unittest.cc
+++ b/src/bin/dhcp6/tests/fqdn_unittest.cc
@@ -145,7 +145,7 @@ public:
             return (DdnsParamsPtr(new DdnsParams()));
         }
 
-        return (CfgMgr::instance().getCurrentCfg()->getDdnsParams(subnet_));
+        return(CfgMgr::instance().getCurrentCfg()->getDdnsParams(subnet_));
     }
 
     /// @brief Construct the DHCPv6 Client FQDN option using flags and
diff --git a/src/hooks/dhcp/lease_cmds/lease_cmds_callouts.cc b/src/hooks/dhcp/lease_cmds/lease_cmds_callouts.cc
index b284aaab3f..7d431b40dd 100644
--- a/src/hooks/dhcp/lease_cmds/lease_cmds_callouts.cc
+++ b/src/hooks/dhcp/lease_cmds/lease_cmds_callouts.cc
@@ -34,7 +34,7 @@ extern "C" {
 /// 1 otherwise.
 int lease4_add(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.leaseAddHandler(handle));
+    return(lease_cmds.leaseAddHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-add' command.
@@ -45,7 +45,7 @@ int lease4_add(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_add(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.leaseAddHandler(handle));
+    return(lease_cmds.leaseAddHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-bulk-apply' command.
@@ -67,7 +67,7 @@ int lease6_bulk_apply(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease4_get(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.leaseGetHandler(handle));
+    return(lease_cmds.leaseGetHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-get' command.
@@ -78,7 +78,7 @@ int lease4_get(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_get(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.leaseGetHandler(handle));
+    return(lease_cmds.leaseGetHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease4-get-all' command.
@@ -188,7 +188,7 @@ int lease6_get_by_hostname(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease4_del(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease4DelHandler(handle));
+    return(lease_cmds.lease4DelHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-del' command.
@@ -199,7 +199,7 @@ int lease4_del(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_del(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease6DelHandler(handle));
+    return(lease_cmds.lease6DelHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease4-update' command.
@@ -210,7 +210,7 @@ int lease6_del(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease4_update(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease4UpdateHandler(handle));
+    return(lease_cmds.lease4UpdateHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-update' command.
@@ -221,7 +221,7 @@ int lease4_update(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_update(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease6UpdateHandler(handle));
+    return(lease_cmds.lease6UpdateHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease4-wipe' command.
@@ -232,7 +232,7 @@ int lease6_update(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease4_wipe(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease4WipeHandler(handle));
+    return(lease_cmds.lease4WipeHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-wipe' command.
@@ -243,7 +243,7 @@ int lease4_wipe(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_wipe(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease6WipeHandler(handle));
+    return(lease_cmds.lease6WipeHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease4-resend-ddns' command.
@@ -254,7 +254,7 @@ int lease6_wipe(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease4_resend_ddns(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease4ResendDdnsHandler(handle));
+    return(lease_cmds.lease4ResendDdnsHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease6-resend-ddns' command.
@@ -265,7 +265,7 @@ int lease4_resend_ddns(CalloutHandle& handle) {
 /// 1 otherwise.
 int lease6_resend_ddns(CalloutHandle& handle) {
     LeaseCmds lease_cmds;
-    return (lease_cmds.lease6ResendDdnsHandler(handle));
+    return(lease_cmds.lease6ResendDdnsHandler(handle));
 }
 
 /// @brief This is a command callout for 'lease4-write' command.
diff --git a/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp4.cc b/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp4.cc
index d70fa258c1..afaceced64 100644
--- a/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp4.cc
+++ b/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp4.cc
@@ -4525,7 +4525,7 @@ PgSqlConfigBackendDHCPv4Impl::getStatement(size_t index) const {
                   << index << ", is invalid");
     }
 
-    return (tagged_statements[index]);
+    return(tagged_statements[index]);
 }
 
 PgSqlConfigBackendDHCPv4::PgSqlConfigBackendDHCPv4(const DatabaseConnection::ParameterMap& parameters)
diff --git a/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp6.cc b/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp6.cc
index b78b4d63e3..5ad7e43188 100644
--- a/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp6.cc
+++ b/src/hooks/dhcp/pgsql_cb/pgsql_cb_dhcp6.cc
@@ -4994,7 +4994,7 @@ PgSqlConfigBackendDHCPv6Impl::getStatement(size_t index) const {
                   << index << ", is invalid");
     }
 
-    return (tagged_statements[index]);
+    return(tagged_statements[index]);
 }
 
 PgSqlConfigBackendDHCPv6::PgSqlConfigBackendDHCPv6(const DatabaseConnection::ParameterMap& parameters)
diff --git a/src/hooks/dhcp/pgsql_cb/pgsql_cb_impl.cc b/src/hooks/dhcp/pgsql_cb/pgsql_cb_impl.cc
index c04eb74c14..4399cb08a2 100644
--- a/src/hooks/dhcp/pgsql_cb/pgsql_cb_impl.cc
+++ b/src/hooks/dhcp/pgsql_cb/pgsql_cb_impl.cc
@@ -50,7 +50,7 @@ PgSqlConfigBackendImpl::insertQuery(size_t index,
 uint64_t
 PgSqlConfigBackendImpl::updateDeleteQuery(size_t index,
                                           const PsqlBindArray& in_bindings) {
-    return (conn_.updateDeleteQuery(getStatement(index), in_bindings));
+    return(conn_.updateDeleteQuery(getStatement(index), in_bindings));
 }
 
 PgSqlConfigBackendImpl::ScopedAuditRevision::ScopedAuditRevision(
diff --git a/src/hooks/dhcp/run_script/tests/run_script_unittests.cc b/src/hooks/dhcp/run_script/tests/run_script_unittests.cc
index 7ca5babee7..46d9c8d277 100644
--- a/src/hooks/dhcp/run_script/tests/run_script_unittests.cc
+++ b/src/hooks/dhcp/run_script/tests/run_script_unittests.cc
@@ -156,7 +156,7 @@ generateLease4() {
     Lease4Ptr lease4(new Lease4(IOAddress("192.168.0.1"), hwaddr, clientid,
                                 2, 3, 4, false, false, "test.hostname"));
 
-    return (lease4);
+    return(lease4);
 }
 
 /// @brief Generate a valid Lease6.
diff --git a/src/hooks/dhcp/stat_cmds/stat_cmds_callouts.cc b/src/hooks/dhcp/stat_cmds/stat_cmds_callouts.cc
index df90c55fe1..228772f981 100644
--- a/src/hooks/dhcp/stat_cmds/stat_cmds_callouts.cc
+++ b/src/hooks/dhcp/stat_cmds/stat_cmds_callouts.cc
@@ -32,7 +32,7 @@ extern "C" {
 /// 1 otherwise.
 int stat_lease4_get(CalloutHandle& handle) {
     StatCmds stat_cmds;
-    return (stat_cmds.statLease4GetHandler(handle));
+    return(stat_cmds.statLease4GetHandler(handle));
 }
 
 /// @brief This is a command callout for 'stat-lease6-get' command.
@@ -43,7 +43,7 @@ int stat_lease4_get(CalloutHandle& handle) {
 /// 1 otherwise.
 int stat_lease6_get(CalloutHandle& handle) {
     StatCmds stat_cmds;
-    return (stat_cmds.statLease6GetHandler(handle));
+    return(stat_cmds.statLease6GetHandler(handle));
 }
 
 /// @brief This function is called when the library is loaded.
diff --git a/src/hooks/dhcp/user_chk/pkt_send_co.cc b/src/hooks/dhcp/user_chk/pkt_send_co.cc
index 788d133022..740bc4b6c3 100644
--- a/src/hooks/dhcp/user_chk/pkt_send_co.cc
+++ b/src/hooks/dhcp/user_chk/pkt_send_co.cc
@@ -402,7 +402,7 @@ void generate_output_record(const std::string& id_type_str,
 std::string getV6AddrStr(Pkt6Ptr response) {
     OptionPtr tmp = response->getOption(D6O_IA_NA);
     if (tmp) {
-        return (getAddrStrIA_NA(tmp));
+        return(getAddrStrIA_NA(tmp));
     }
 
     // IA_NA not there so try IA_PD
@@ -411,7 +411,7 @@ std::string getV6AddrStr(Pkt6Ptr response) {
         isc_throw (isc::BadValue, "Response has neither IA_NA nor IA_PD");
     }
 
-    return (getAddrStrIA_PD(tmp));
+    return(getAddrStrIA_PD(tmp));
 }
 
 /// @brief Stringify the lease address in an D6O_IA_NA option set
diff --git a/src/hooks/dhcp/user_chk/user_file.cc b/src/hooks/dhcp/user_chk/user_file.cc
index e324bcb2b0..96cb6a0fc4 100644
--- a/src/hooks/dhcp/user_chk/user_file.cc
+++ b/src/hooks/dhcp/user_chk/user_file.cc
@@ -54,7 +54,7 @@ UserFile::readNextUser() {
 
         // We got something, try to make a user out of it.
         if (file_.gcount() > 0) {
-            return (makeUser(buf));
+            return(makeUser(buf));
         }
     }
 
diff --git a/src/lib/database/dbaccess_parser.cc b/src/lib/database/dbaccess_parser.cc
index 76ba13799e..caee236282 100644
--- a/src/lib/database/dbaccess_parser.cc
+++ b/src/lib/database/dbaccess_parser.cc
@@ -91,7 +91,6 @@ DbAccessParser::parse(std::string& access_string,
                 max_row_errors = param.second->intValue();
                 values_copy[param.first] =
                     boost::lexical_cast<std::string>(max_row_errors);
-
             } else {
 
                 // all remaining string parameters
diff --git a/src/lib/dhcp/classify.h b/src/lib/dhcp/classify.h
index 0c857048ea..f7d38c4c39 100644
--- a/src/lib/dhcp/classify.h
+++ b/src/lib/dhcp/classify.h
@@ -64,9 +64,9 @@ namespace dhcp {
     > ClientClassContainer;
 
     /// @brief Defines a single subclass (template class instantiation).
-    struct SubClass {
+    struct SubClassRelation {
         /// @brief Constructor.
-        SubClass(const ClientClass& template_class, const ClientClass& subclass) :
+        SubClassRelation(const ClientClass& template_class, const ClientClass& subclass) :
               template_class_(template_class), subclass_(subclass) {
         }
 
@@ -77,6 +77,30 @@ namespace dhcp {
         ClientClass subclass_;
     };
 
+    /// @brief Tag for the sequence index.
+    struct TemplateClassSequenceTag { };
+
+    /// @brief Tag for the name index.
+    struct TemplateClassNameTag { };
+
+    /// @brief the subclass multi-index.
+    typedef boost::multi_index_container<
+        SubClassRelation,
+        boost::multi_index::indexed_by<
+            // First index is the sequence one.
+            boost::multi_index::sequenced<
+                boost::multi_index::tag<TemplateClassSequenceTag>
+            >,
+            // Second index is the name hash one.
+            boost::multi_index::hashed_unique<
+                boost::multi_index::tag<TemplateClassNameTag>,
+                boost::multi_index::member<SubClassRelation,
+                                           ClientClass,
+                                           &SubClassRelation::template_class_>
+            >
+        >
+    > SubClassRelationContainer;
+
     /// @brief Container for storing client class names
     ///
     /// Both a list to iterate on it in insert order and unordered
diff --git a/src/lib/dhcp/pkt.cc b/src/lib/dhcp/pkt.cc
index f70043edf2..fa85b0070b 100644
--- a/src/lib/dhcp/pkt.cc
+++ b/src/lib/dhcp/pkt.cc
@@ -77,10 +77,7 @@ Pkt::delOption(uint16_t type) {
 
 bool
 Pkt::inClass(const ClientClass& client_class) {
-    if (classes_.contains(client_class)) {
-        return (true);
-    }
-    return (subclasses_.contains(client_class));
+    return (classes_.contains(client_class));
 }
 
 void
@@ -92,9 +89,7 @@ Pkt::addClass(const ClientClass& client_class, bool required) {
     ClientClasses& classes = !required ? classes_ : required_classes_;
     if (!classes.contains(client_class)) {
         classes.insert(client_class);
-        if (!subclasses_.empty()) {
-            subclasses_.insert(client_class);
-        }
+        static_cast<void>(subclasses_.push_back(SubClassRelation(client_class, client_class)));
     }
 }
 
@@ -105,11 +100,12 @@ Pkt::addSubClass(const ClientClass& template_class, const ClientClass& subclass)
         classes_.insert("ALL");
     }
     if (!classes_.contains(template_class)) {
-        if (subclasses_.empty()) {
-            subclasses_ = classes_;
-        }
         classes_.insert(template_class);
-        subclasses_.insert(subclass);
+        static_cast<void>(subclasses_.push_back(SubClassRelation(template_class, subclass)));
+    }
+    if (!classes_.contains(subclass)) {
+        classes_.insert(subclass);
+        static_cast<void>(subclasses_.push_back(SubClassRelation(subclass, subclass)));
     }
 }
 
diff --git a/src/lib/dhcp/pkt.h b/src/lib/dhcp/pkt.h
index 89cfb4c39c..dd1e395f39 100644
--- a/src/lib/dhcp/pkt.h
+++ b/src/lib/dhcp/pkt.h
@@ -327,13 +327,6 @@ public:
         return (!required ? classes_ : required_classes_);
     }
 
-    /// @brief Returns true if the subclass set is not empty
-    ///
-    /// @return true if there is at least one subclass associated with the packet.
-    bool hasSubClasses() const {
-        return (!subclasses_.empty());
-    }
-
     /// @brief Returns the class set including template classes associated with
     /// subclasses
     ///
@@ -343,10 +336,7 @@ public:
     /// @return if required is false (the default) the classes the
     /// packet belongs to else the classes which are required to be
     /// evaluated.
-    const ClientClasses getClassesAndSubClasses() const {
-        if (subclasses_.empty()) {
-            return (classes_);
-        }
+    const SubClassRelationContainer& getSubClassesRelations() const {
         return (subclasses_);
     }
 
@@ -662,7 +652,7 @@ public:
     /// iterate over existing classes. Having it public also solves the problem
     /// of returned reference lifetime. It is preferred to use @ref inClass and
     /// @ref addSubClass to operate on this field.
-    ClientClasses subclasses_;
+    SubClassRelationContainer subclasses_;
 
     /// @brief Collection of options present in this message.
     ///
diff --git a/src/lib/dhcp/tests/pkt4_unittest.cc b/src/lib/dhcp/tests/pkt4_unittest.cc
index 1bd45b5ce6..4687835a87 100644
--- a/src/lib/dhcp/tests/pkt4_unittest.cc
+++ b/src/lib/dhcp/tests/pkt4_unittest.cc
@@ -933,14 +933,12 @@ TEST_F(Pkt4Test, clientClasses) {
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_EROUTER));
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_MODEM));
     EXPECT_TRUE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first class
     pkt.addClass(DOCSIS3_CLASS_EROUTER);
     EXPECT_TRUE(pkt.inClass(DOCSIS3_CLASS_EROUTER));
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_MODEM));
     ASSERT_FALSE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to a second class
     pkt.addClass(DOCSIS3_CLASS_MODEM);
@@ -951,7 +949,6 @@ TEST_F(Pkt4Test, clientClasses) {
     EXPECT_NO_THROW(pkt.addClass("foo"));
     EXPECT_NO_THROW(pkt.addClass("foo"));
     EXPECT_NO_THROW(pkt.addClass("foo"));
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Check that the packet belongs to 'foo'
     EXPECT_TRUE(pkt.inClass("foo"));
@@ -964,17 +961,14 @@ TEST_F(Pkt4Test, deferredClientClasses) {
 
     // Default values (do not belong to any class)
     EXPECT_TRUE(pkt.getClasses(true).empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first class
     pkt.addClass(DOCSIS3_CLASS_EROUTER, true);
     EXPECT_EQ(1, pkt.getClasses(true).size());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to a second class
     pkt.addClass(DOCSIS3_CLASS_MODEM, true);
     EXPECT_EQ(2, pkt.getClasses(true).size());
-    EXPECT_FALSE(pkt.hasSubClasses());
     EXPECT_TRUE(pkt.getClasses(true).contains(DOCSIS3_CLASS_EROUTER));
     EXPECT_TRUE(pkt.getClasses(true).contains(DOCSIS3_CLASS_MODEM));
     EXPECT_FALSE(pkt.getClasses(true).contains("foo"));
@@ -983,7 +977,6 @@ TEST_F(Pkt4Test, deferredClientClasses) {
     EXPECT_NO_THROW(pkt.addClass("foo", true));
     EXPECT_NO_THROW(pkt.addClass("foo", true));
     EXPECT_NO_THROW(pkt.addClass("foo", true));
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Check that the packet belongs to 'foo'
     EXPECT_TRUE(pkt.getClasses(true).contains("foo"));
@@ -998,14 +991,12 @@ TEST_F(Pkt4Test, templateClasses) {
     EXPECT_FALSE(pkt.inClass("eth0"));
     EXPECT_FALSE(pkt.inClass("interface-id0"));
     EXPECT_TRUE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first subclass
     pkt.addSubClass("template-interface-name", "eth0");
     EXPECT_TRUE(pkt.inClass("eth0"));
     EXPECT_FALSE(pkt.inClass("interface-id0"));
     ASSERT_FALSE(pkt.getClasses().empty());
-    EXPECT_TRUE(pkt.hasSubClasses());
 
     // Add to a second subclass
     pkt.addSubClass("template-interface-id", "interface-id0");
diff --git a/src/lib/dhcp/tests/pkt6_unittest.cc b/src/lib/dhcp/tests/pkt6_unittest.cc
index f92f4168f5..f433bae6b6 100644
--- a/src/lib/dhcp/tests/pkt6_unittest.cc
+++ b/src/lib/dhcp/tests/pkt6_unittest.cc
@@ -1307,14 +1307,12 @@ TEST_F(Pkt6Test, clientClasses) {
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_EROUTER));
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_MODEM));
     EXPECT_TRUE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first class
     pkt.addClass(DOCSIS3_CLASS_EROUTER);
     EXPECT_TRUE(pkt.inClass(DOCSIS3_CLASS_EROUTER));
     EXPECT_FALSE(pkt.inClass(DOCSIS3_CLASS_MODEM));
     ASSERT_FALSE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to a second class
     pkt.addClass(DOCSIS3_CLASS_MODEM);
@@ -1325,7 +1323,6 @@ TEST_F(Pkt6Test, clientClasses) {
     EXPECT_NO_THROW(pkt.addClass("foo"));
     EXPECT_NO_THROW(pkt.addClass("foo"));
     EXPECT_NO_THROW(pkt.addClass("foo"));
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Check that the packet belongs to 'foo'
     EXPECT_TRUE(pkt.inClass("foo"));
@@ -1338,17 +1335,14 @@ TEST_F(Pkt6Test, deferredClientClasses) {
 
     // Default values (do not belong to any class)
     EXPECT_TRUE(pkt.getClasses(true).empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first class
     pkt.addClass(DOCSIS3_CLASS_EROUTER, true);
     EXPECT_EQ(1, pkt.getClasses(true).size());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to a second class
     pkt.addClass(DOCSIS3_CLASS_MODEM, true);
     EXPECT_EQ(2, pkt.getClasses(true).size());
-    EXPECT_FALSE(pkt.hasSubClasses());
     EXPECT_TRUE(pkt.getClasses(true).contains(DOCSIS3_CLASS_EROUTER));
     EXPECT_TRUE(pkt.getClasses(true).contains(DOCSIS3_CLASS_MODEM));
     EXPECT_FALSE(pkt.getClasses(true).contains("foo"));
@@ -1357,7 +1351,6 @@ TEST_F(Pkt6Test, deferredClientClasses) {
     EXPECT_NO_THROW(pkt.addClass("foo", true));
     EXPECT_NO_THROW(pkt.addClass("foo", true));
     EXPECT_NO_THROW(pkt.addClass("foo", true));
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Check that the packet belongs to 'foo'
     EXPECT_TRUE(pkt.getClasses(true).contains("foo"));
@@ -1372,14 +1365,12 @@ TEST_F(Pkt6Test, templateClasses) {
     EXPECT_FALSE(pkt.inClass("eth0"));
     EXPECT_FALSE(pkt.inClass("interface-id0"));
     EXPECT_TRUE(pkt.getClasses().empty());
-    EXPECT_FALSE(pkt.hasSubClasses());
 
     // Add to the first subclass
     pkt.addSubClass("template-interface-name", "eth0");
     EXPECT_TRUE(pkt.inClass("eth0"));
     EXPECT_FALSE(pkt.inClass("interface-id0"));
     ASSERT_FALSE(pkt.getClasses().empty());
-    EXPECT_TRUE(pkt.hasSubClasses());
 
     // Add to a second subclass
     pkt.addSubClass("template-interface-id", "interface-id0");
diff --git a/src/lib/dhcpsrv/alloc_engine.cc b/src/lib/dhcpsrv/alloc_engine.cc
index b514055669..9fcdcce2ec 100644
--- a/src/lib/dhcpsrv/alloc_engine.cc
+++ b/src/lib/dhcpsrv/alloc_engine.cc
@@ -425,7 +425,7 @@ inAllowedPool(AllocEngine::ClientContext6& ctx, const Lease::Type& lease_type,
     // If the subnet belongs to a shared network we will be iterating
     // over the subnets that belong to this shared network.
     Subnet6Ptr current_subnet = ctx.subnet_;
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     while (current_subnet) {
         if (current_subnet->clientSupported(classes)) {
@@ -658,7 +658,7 @@ AllocEngine::findReservation(ClientContext6& ctx) {
         }
     }
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     // We can only search for the reservation if a subnet has been selected.
     while (subnet) {
@@ -919,7 +919,7 @@ AllocEngine::allocateUnreservedLeases6(ClientContext6& ctx) {
 
     CalloutHandle::CalloutNextStep callout_status = CalloutHandle::NEXT_STEP_CONTINUE;
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     for (; subnet; subnet = subnet->getNextSubnet(original_subnet)) {
         if (!subnet->clientSupported(classes)) {
@@ -1360,7 +1360,7 @@ AllocEngine::allocateReservedLeases6(ClientContext6& ctx,
     // There is no lease for a reservation in this IA. So, let's now iterate
     // over reservations specified and try to allocate one of them for the IA.
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
     for (Subnet6Ptr subnet = ctx.subnet_; subnet;
          subnet = subnet->getNextSubnet(ctx.subnet_)) {
 
@@ -2259,7 +2259,7 @@ AllocEngine::extendLease6(ClientContext6& ctx, Lease6Ptr lease) {
     // is not permitted by subnet client classification, delete it.
     if (!(ctx.hasGlobalReservation(makeIPv6Resrv(*lease))) &&
         (((lease->type_ != Lease::TYPE_PD) && !ctx.subnet_->inRange(lease->addr_)) ||
-        !ctx.subnet_->clientSupported(ctx.query_->getClassesAndSubClasses()))) {
+        !ctx.subnet_->clientSupported(ctx.query_->getClasses()))) {
         // Oh dear, the lease is no longer valid. We need to get rid of it.
 
         // Remove this lease from LeaseMgr
@@ -3290,7 +3290,7 @@ hasAddressReservation(AllocEngine::ClientContext4& ctx) {
 
         // No address reservation found here, so let's try another subnet
         // within the same shared network.
-        subnet = subnet->getNextSubnet(ctx.subnet_, ctx.query_->getClassesAndSubClasses());
+        subnet = subnet->getNextSubnet(ctx.subnet_, ctx.query_->getClasses());
     }
 
     return (false);
@@ -3316,7 +3316,7 @@ void findClientLease(AllocEngine::ClientContext4& ctx, Lease4Ptr& client_lease)
 
     Subnet4Ptr original_subnet = ctx.subnet_;
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     // Client identifier is optional. First check if we can try to lookup
     // by client-id.
@@ -3401,7 +3401,7 @@ inAllowedPool(AllocEngine::ClientContext4& ctx, const IOAddress& address) {
     // If the subnet belongs to a shared network we will be iterating
     // over the subnets that belong to this shared network.
     Subnet4Ptr current_subnet = ctx.subnet_;
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     while (current_subnet) {
         if (current_subnet->inPool(Lease::TYPE_V4, address, classes)) {
@@ -3513,7 +3513,7 @@ AllocEngine::allocateLease4(ClientContext4& ctx) {
     // subnets allowed for this client within the shared network, we
     // can't allocate a lease.
     Subnet4Ptr subnet = ctx.subnet_;
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
     if (subnet && !subnet->clientSupported(classes)) {
         ctx.subnet_ = subnet->getNextSubnet(subnet, classes);
     }
@@ -3604,7 +3604,7 @@ AllocEngine::findReservation(ClientContext4& ctx) {
         }
     }
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
     // We can only search for the reservation if a subnet has been selected.
     while (subnet) {
 
@@ -4411,7 +4411,7 @@ AllocEngine::allocateUnreservedLease4(ClientContext4& ctx) {
     // no matching pools for the client.
     uint64_t subnets_with_unavail_pools = 0;
 
-    auto const& classes = ctx.query_->getClassesAndSubClasses();
+    auto const& classes = ctx.query_->getClasses();
 
     while (subnet) {
         ClientIdPtr client_id;
diff --git a/src/lib/dhcpsrv/client_class_def.cc b/src/lib/dhcpsrv/client_class_def.cc
index 53e229994d..53e382bde9 100644
--- a/src/lib/dhcpsrv/client_class_def.cc
+++ b/src/lib/dhcpsrv/client_class_def.cc
@@ -294,7 +294,13 @@ ClientClassDef::toElement() const {
 ElementPtr
 TemplateClientClassDef::toElement() const {
     auto const& result = ClientClassDef::toElement();
-    result->set("template-class", Element::create(true));
+    auto const& test = result->get("test");
+    if (test) {
+        result->set("template-test", test);
+        result->remove("test");
+    } else {
+        result->set("template-test", Element::create(""));
+    }
     return (result);
 }
 
diff --git a/src/lib/dhcpsrv/memfile_lease_mgr.cc b/src/lib/dhcpsrv/memfile_lease_mgr.cc
index 61c8ce8747..c62fe59610 100644
--- a/src/lib/dhcpsrv/memfile_lease_mgr.cc
+++ b/src/lib/dhcpsrv/memfile_lease_mgr.cc
@@ -1882,7 +1882,7 @@ Memfile_LeaseMgr::loadLeasesFromFiles(const std::string& filename,
     lease_file.reset(new LeaseFileType(filename));
     LeaseFileLoader::load<LeaseObjectType>(*lease_file, storage,
                                            max_row_errors, false);
-    conversion_needed = conversion_needed || lease_file->needsConversion();
+    conversion_needed =  conversion_needed || lease_file->needsConversion();
 
     return (conversion_needed);
 }
@@ -2006,7 +2006,7 @@ Memfile_LeaseMgr::startLeaseStatsQuery4() {
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 LeaseStatsQueryPtr
@@ -2019,7 +2019,7 @@ Memfile_LeaseMgr::startSubnetLeaseStatsQuery4(const SubnetID& subnet_id) {
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 LeaseStatsQueryPtr
@@ -2034,7 +2034,7 @@ Memfile_LeaseMgr::startSubnetRangeLeaseStatsQuery4(const SubnetID& first_subnet_
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 LeaseStatsQueryPtr
@@ -2047,7 +2047,7 @@ Memfile_LeaseMgr::startLeaseStatsQuery6() {
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 LeaseStatsQueryPtr
@@ -2060,7 +2060,7 @@ Memfile_LeaseMgr::startSubnetLeaseStatsQuery6(const SubnetID& subnet_id) {
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 LeaseStatsQueryPtr
@@ -2075,7 +2075,7 @@ Memfile_LeaseMgr::startSubnetRangeLeaseStatsQuery6(const SubnetID& first_subnet_
         query->start();
     }
 
-    return (query);
+    return(query);
 }
 
 size_t
@@ -2163,15 +2163,15 @@ Memfile_LeaseMgr::getClassLeaseCount(const ClientClass& client_class,
                                      const Lease::Type& ltype /* = Lease::TYPE_V4*/) const {
     if (MultiThreadingMgr::instance().getMode()) {
         std::lock_guard<std::mutex> lock(*mutex_);
-        return (class_lease_counter_.getClassCount(client_class, ltype));
+        return(class_lease_counter_.getClassCount(client_class, ltype));
     } else {
-        return (class_lease_counter_.getClassCount(client_class, ltype));
+        return(class_lease_counter_.getClassCount(client_class, ltype));
     }
 }
 
 void
 Memfile_LeaseMgr::clearClassLeaseCounts() {
-    return (class_lease_counter_.clear());
+    return(class_lease_counter_.clear());
 }
 
 std::string
diff --git a/src/lib/dhcpsrv/parsers/client_class_def_parser.cc b/src/lib/dhcpsrv/parsers/client_class_def_parser.cc
index 8c48a9afbc..99e6692571 100644
--- a/src/lib/dhcpsrv/parsers/client_class_def_parser.cc
+++ b/src/lib/dhcpsrv/parsers/client_class_def_parser.cc
@@ -50,6 +50,12 @@ ExpressionParser::parse(ExpressionPtr& expression,
     // by str() enclosed in quotes.
     std::string value;
     expression_cfg->getValue(value);
+
+    if (parser_type == EvalContext::PARSER_STRING && value.empty()) {
+        isc_throw(DhcpConfigError, "expression can not be empty at ("
+            << expression_cfg->getPosition() << ")");
+    }
+
     try {
         EvalContext eval_ctx(family == AF_INET ? Option::V4 : Option::V6,
                              check_defined);
@@ -83,29 +89,33 @@ ClientClassDefParser::parse(ClientClassDictionaryPtr& class_dictionary,
 
     EvalContext::ParserType parser_type = EvalContext::PARSER_BOOL;
 
-    // Let's try to parse the template-class flag
+    // Let's try to parse the template-test expression
     bool is_template = false;
-    if (class_def_cfg->contains("template-class")) {
-        is_template = getBoolean(class_def_cfg, "template-class");
-        if (is_template) {
-            parser_type = EvalContext::PARSER_STRING;
-        }
-    }
 
     // Parse matching expression
     ExpressionPtr match_expr;
     ConstElementPtr test_cfg = class_def_cfg->get("test");
+    ConstElementPtr template_test_cfg = class_def_cfg->get("template-test");
+    if (test_cfg && template_test_cfg) {
+        isc_throw(DhcpConfigError, "expected either 'test' or 'template-test' ("
+                  << test_cfg->getPosition() << ") and ("
+                  << template_test_cfg->getPosition() << ")");
+    }
     std::string test;
     bool depend_on_known = false;
+    EvalContext::CheckDefined check_defined = EvalContext::acceptAll;
+    if (template_test_cfg) {
+        test_cfg = template_test_cfg;
+        parser_type = EvalContext::PARSER_STRING;
+        is_template = true;
+    } else {
+        check_defined = [&class_dictionary, &depend_on_known, check_dependencies](const ClientClass& cclass) {
+            return (!check_dependencies || isClientClassDefined(class_dictionary, depend_on_known, cclass));
+        };
+    }
+
     if (test_cfg) {
         ExpressionParser parser;
-        auto check_defined =
-            [&class_dictionary, &depend_on_known, check_dependencies]
-            (const ClientClass& cclass) {
-                return (!check_dependencies || isClientClassDefined(class_dictionary,
-                                                                    depend_on_known,
-                                                                    cclass));
-        };
         parser.parse(match_expr, test_cfg, family, check_defined, parser_type);
         test = test_cfg->stringValue();
     }
@@ -285,7 +295,7 @@ ClientClassDefParser::checkParametersSupported(const ConstElementPtr& class_def_
                                                       "valid-lifetime",
                                                       "min-valid-lifetime",
                                                       "max-valid-lifetime",
-                                                      "template-class"};
+                                                      "template-test"};
 
     // The v4 client class supports additional parameters.
     static std::set<std::string> supported_params_v4 = { "option-def",
diff --git a/src/lib/dhcpsrv/tests/client_class_def_parser_unittest.cc b/src/lib/dhcpsrv/tests/client_class_def_parser_unittest.cc
index 305d024c52..0ca5f0450a 100644
--- a/src/lib/dhcpsrv/tests/client_class_def_parser_unittest.cc
+++ b/src/lib/dhcpsrv/tests/client_class_def_parser_unittest.cc
@@ -378,7 +378,7 @@ TEST_F(ClientClassDefParserTest, checkAllSupported4) {
         "    \"min-valid-lifetime\": 1000,\n"
         "    \"max-valid-lifetime\": 1000,\n"
         "    \"next-server\": \"192.0.2.3\",\n"
-        "    \"template-class\": true,\n"
+        "    \"template-test\": \"\",\n"
         "    \"server-hostname\": \"myhost\",\n"
         "    \"boot-file-name\": \"efi\""
         "}\n";
@@ -400,7 +400,7 @@ TEST_F(ClientClassDefParserTest, checkAllSupported6) {
         "    \"option-data\": [ ],\n"
         "    \"user-context\": { },\n"
         "    \"only-if-required\": false,\n"
-        "    \"template-class\": true,\n"
+        "    \"template-test\": \"\",\n"
         "    \"preferred-lifetime\": 800,\n"
         "    \"min-preferred-lifetime\": 800,\n"
         "    \"max-preferred-lifetime\": 800\n"
@@ -638,8 +638,7 @@ TEST_F(ClientClassDefParserTest, templateNameAndExpressionClass4) {
     std::string cfg_text =
         "{ \n"
         "    \"name\": \"class_one\", \n"
-        "    \"template-class\": true, \n"
-        "    \"test\": \"" + test + "\" \n"
+        "    \"template-test\": \"" + test + "\" \n"
         "} \n";
 
     ClientClassDefPtr cclass;
@@ -730,8 +729,7 @@ TEST_F(ClientClassDefParserTest, templateNameAndExpressionClass6) {
     std::string cfg_text =
         "{ \n"
         "    \"name\": \"class_one\", \n"
-        "    \"template-class\": true, \n"
-        "    \"test\": \"" + test + "\" \n"
+        "    \"template-test\": \"" + test + "\" \n"
         "} \n";
 
     ClientClassDefPtr cclass;
@@ -894,8 +892,7 @@ TEST_F(ClientClassDefParserTest, templateBasicValidClass4) {
     std::string cfg_text =
         "{ \n"
         "    \"name\": \"MICROSOFT\", \n"
-        "    \"test\": \"" + test + "\", \n"
-        "    \"template-class\": true, \n"
+        "    \"template-test\": \"" + test + "\", \n"
         "    \"option-data\": [ \n"
         "        { \n"
         "           \"name\": \"domain-name-servers\", \n"
@@ -994,8 +991,7 @@ TEST_F(ClientClassDefParserTest, templateBasicValidClass6) {
     std::string cfg_text =
         "{ \n"
         "    \"name\": \"MICROSOFT\", \n"
-        "    \"test\": \"" + test + "\", \n"
-        "    \"template-class\": true, \n"
+        "    \"template-test\": \"" + test + "\", \n"
         "    \"option-data\": [ \n"
         "        { \n"
         "           \"name\": \"sip-server-addr\", \n"
@@ -1095,13 +1091,38 @@ TEST_F(ClientClassDefParserTest, invalidExpression) {
                  DhcpConfigError);
 }
 
-// Verifies that a class with an invalid expression, fails to parse.
+// Verifies that a class with an invalid template expression, fails to parse.
 TEST_F(ClientClassDefParserTest, templateInvalidExpression) {
     std::string cfg_text =
         "{ \n"
         "    \"name\": \"one\", \n"
-        "    \"template-class\": true, \n"
-        "    \"test\": 777 \n"
+        "    \"template-test\": 777 \n"
+        "} \n";
+
+    ClientClassDefPtr cclass;
+    ASSERT_THROW(cclass = parseClientClassDef(cfg_text, AF_INET6),
+                 DhcpConfigError);
+}
+
+// Verifies that a class with an empty expression, fails to parse.
+TEST_F(ClientClassDefParserTest, emptyExpression) {
+    std::string cfg_text =
+        "{ \n"
+        "    \"name\": \"one\", \n"
+        "    \"test\": \"\" \n"
+        "} \n";
+
+    ClientClassDefPtr cclass;
+    ASSERT_THROW(cclass = parseClientClassDef(cfg_text, AF_INET6),
+                 DhcpConfigError);
+}
+
+// Verifies that a class with an empty expression, fails to parse.
+TEST_F(ClientClassDefParserTest, templateEmptyExpression) {
+    std::string cfg_text =
+        "{ \n"
+        "    \"name\": \"one\", \n"
+        "    \"template-test\": \"\" \n"
         "} \n";
 
     ClientClassDefPtr cclass;
@@ -1109,6 +1130,20 @@ TEST_F(ClientClassDefParserTest, templateInvalidExpression) {
                  DhcpConfigError);
 }
 
+// Verifies that a class with both test and template-test expressions, fails to parse.
+TEST_F(ClientClassDefParserTest, bothTestAndTemplateTestExpressions) {
+    std::string cfg_text =
+        "{ \n"
+        "    \"name\": \"one\", \n"
+        "    \"test\": \"true\", \n"
+        "    \"template-test\": \"\" \n"
+        "} \n";
+
+    ClientClassDefPtr cclass;
+    ASSERT_THROW(cclass = parseClientClassDef(cfg_text, AF_INET),
+                 DhcpConfigError);
+}
+
 // Verifies that a class with invalid option-def, fails to parse.
 TEST_F(ClientClassDefParserTest, invalidOptionDef) {
     std::string cfg_text =
@@ -1187,15 +1222,15 @@ TEST_F(ClientClassDefListParserTest, templateSimpleValidList) {
         "[ \n"
         "   { \n"
         "       \"name\": \"one\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"two\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"three\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   } \n"
         "] \n";
 
@@ -1257,15 +1292,15 @@ TEST_F(ClientClassDefListParserTest, templateDuplicateClass) {
         "[ \n"
         "   { \n"
         "       \"name\": \"one\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"two\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   }, \n"
         "   { \n"
         "       \"name\": \"two\", \n"
-        "       \"template-class\": true \n"
+        "       \"template-test\": \"''\" \n"
         "   } \n"
         "] \n";
 
diff --git a/src/lib/dhcpsrv/tests/client_class_def_unittest.cc b/src/lib/dhcpsrv/tests/client_class_def_unittest.cc
index f0f0e8451f..e7894a52c3 100644
--- a/src/lib/dhcpsrv/tests/client_class_def_unittest.cc
+++ b/src/lib/dhcpsrv/tests/client_class_def_unittest.cc
@@ -1510,7 +1510,7 @@ TEST(TemplateClientClassDef, unparseDef) {
     std::string name = "class1";
     ExpressionPtr expr;
     ASSERT_NO_THROW(cclass.reset(new TemplateClientClassDef(name, expr)));
-    std::string test = "option[12].text == 'foo'";
+    std::string test = "option[12].text";
     cclass->setTest(test);
     std::string comment = "bar";
     std::string user_context = "{ \"comment\": \"" + comment + "\", ";
@@ -1529,11 +1529,10 @@ TEST(TemplateClientClassDef, unparseDef) {
     // Unparse it
     std::string expected = "{\n"
         "\"name\": \"" + name + "\",\n"
-        "\"test\": \"" + test + "\",\n"
+        "\"template-test\": \"" + test + "\",\n"
         "\"only-if-required\": true,\n"
         "\"next-server\": \"" + next_server + "\",\n"
         "\"server-hostname\": \"" + sname + "\",\n"
-        "\"template-class\": true,\n"
         "\"boot-file-name\": \"" + filename + "\",\n"
         "\"option-data\": [ ],\n"
         "\"user-context\": { \"bar\": 1,\n"
@@ -1573,7 +1572,7 @@ TEST(ClientClassDictionary, templateUnparseDict) {
                     "\"name\": \"" + name + "\",\n"
                     "\"next-server\": \"0.0.0.0\",\n"
                     "\"server-hostname\": \"\",\n"
-                    "\"template-class\": true,\n"
+                    "\"template-test\": \"\",\n"
                     "\"boot-file-name\": \"\",\n"
                     "\"option-data\": [ ] }");
     };