[trac812next] use AbstractMessageRenderer for toWire().

not directly related to the main subject for this branch, but we need
this fix to make the main code work correctly.

src/lib/dns/rrclass-placeholder.h

@@ -31,7 +31,7 @@ class OutputBuffer;
 namespace dns {
 
 // forward declarations
-class MessageRenderer;
+class AbstractMessageRenderer;
 
 ///
 /// \brief A standard DNS module exception that is thrown if an RRClass object
@@ -169,7 +169,7 @@ public:
     /// standard exception will be thrown.
     ///
     /// \param buffer An output buffer to store the wire data.
-    void toWire(MessageRenderer& renderer) const;
+    void toWire(AbstractMessageRenderer& renderer) const;
     /// \brief Render the \c RRClass in the wire format.
     ///
     /// This method renders the class code in network byte order into the

src/lib/dns/rrclass.cc

@@ -52,7 +52,7 @@ RRClass::toWire(OutputBuffer& buffer) const {
 }
 
 void
-RRClass::toWire(MessageRenderer& renderer) const {
+RRClass::toWire(AbstractMessageRenderer& renderer) const {
     renderer.writeUint16(classcode_);
 }
 

src/lib/dns/tests/testdata/message_toWire2.spec

@@ -0,0 +1,21 @@
+#
+# A simple DNS response message with TSIG signed
+#
+
+[custom]
+sections: header:question:tsig
+[header]
+id: 0x2d65
+rd: 1
+arcount: 1
+[question]
+name: www.example.com
+[tsig]
+as_rr: True
+# TSIG QNAME won't be compressed
+rr_name: www.example.com
+algorithm: hmac-md5
+time_signed: 0x4da8877a
+mac_size: 16
+mac: 0x227026ad297beee721ce6c6fff1e9ef3  
+original_id: 0x2d65

src/lib/dns/tests/testdata/message_toWire3.spec

@@ -0,0 +1,22 @@
+#
+# A simple DNS response message with EDNS and TSIG
+#
+
+[custom]
+sections: header:question:edns:tsig
+[header]
+id: 0x06cd
+rd: 1
+arcount: 2
+[question]
+name: www.example.com
+[edns]
+[tsig]
+as_rr: True
+# TSIG QNAME won't be compressed
+rr_name: www.example.com
+algorithm: hmac-md5
+time_signed: 0x4db60d1f
+mac_size: 16
+mac: 0x93444053881c83d7eb120e86f25b369e
+original_id: 0x06cd

src/lib/dns/tests/testdata/tsigrecord_toWire1.spec

@@ -0,0 +1,15 @@
+#
+# A simple DNS response message with TSIG signed
+#
+
+[custom]
+sections: tsig
+[tsig]
+as_rr: True
+# TSIG QNAME won't be compressed
+rr_name: www.example.com
+algorithm: hmac-md5
+time_signed: 0x4da8877a
+mac_size: 16
+mac: 0xdadadadadadadadadadadadadadadada
+original_id: 0x2d65