[2976] Implemented the rest of the toWire test.

src/bin/d2/tests/d2_update_message_unittests.cc

@@ -49,17 +49,26 @@ public:
     // @param buf input buffer, its internal pointer will be moved to
     //        the position after a name being read from it.
     // @param name_length length of the name stored in the buffer
+    // @param no_zero_byte if true it indicates that the given buffer does not
+    //        comprise the zero byte, which signals end of the name. This is
+    //        the case, when dealing with compressed messages which don't have
+    //        this byte.
     //
     // @return string representation of the name.
-    std::string readNameFromWire(InputBuffer& buf, const size_t name_length) {
+    std::string readNameFromWire(InputBuffer& buf, size_t name_length,
+                                 bool no_zero_byte = false) {
         // 64 characters bytes should be sufficent for current tests.
         // It may be extended if required.
         char name_data[64];
         // Create another InputBuffer which holds only the name in the wire
         // format.
         buf.readData(name_data, name_length);
+        if (no_zero_byte) {
+            ++name_length;
+            name_data[name_length-1] = 0;
+        }
         InputBuffer name_buf(name_data, name_length);
-        // Parse the name and returns its textual representation.
+        // Parse the name and return its textual representation.
         Name name(name_buf);
         return (name.toText());
     }
@@ -193,6 +202,74 @@ TEST_F(D2UpdateMessageTest, toWire) {
     // In case of this message, we expect to have two prerequisite RRs.
     // Their structure is checked below.
 
+    // First prerequisite should comprise the 'Name is not in use prerequisite'
+    // for 'foo.example.com'.
+
+    // Check the name first. Message renderer is using compression for domain
+    // names as described in RFC 1035, section 4.1.4. The name in this RR is
+    // foo.example.com. The name of the zone is example.com and it has occured
+    // in this message already at offset 12 (the size of the header is 12).
+    // Therefore, name of this RR is encoded as 'foo', followed by a pointer
+    // to offset in this message where the remainder of this name was used.
+    // This pointer has the following format:
+    // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+    // | 1  1|                 OFFSET                  |
+    // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+    // | 1  1| 0  0  0  0  0  0  0  0  0  0  1  1  0  0|
+    // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
+    // which has a following hexadecimal representation: 0xC00C
+
+    // Let's read the non-compressed part first - 'foo.'
+    std::string name_prereq1 = readNameFromWire(buf, 4, true);
+    EXPECT_EQ("foo.", name_prereq1);
+    // The remaining two bytes hold the pointer to 'example.com'.
+    EXPECT_EQ(0xC00C, buf.readUint16());
+    // TYPE is ANY
+    EXPECT_EQ(RRType::ANY().getCode(), buf.readUint16());
+    // CLASS is NONE
+    EXPECT_EQ(RRClass::NONE().getCode(), buf.readUint16());
+    // TTL is a 32-but value, expecting 0
+    EXPECT_EQ(0, buf.readUint32());
+    // There is no RDATA, so RDLENGTH is 0
+    EXPECT_EQ(0, buf.readUint16());
+
+    // Start checking second prerequisite.
+
+    std::string name_prereq2 = readNameFromWire(buf, 4, true);
+    EXPECT_EQ("bar.", name_prereq2);
+    // The remaining two bytes hold the pointer to 'example.com'.
+    EXPECT_EQ(0xC00C, buf.readUint16());
+    // TYPE is ANY
+    EXPECT_EQ(RRType::ANY().getCode(), buf.readUint16());
+    // CLASS is ANY
+    EXPECT_EQ(RRClass::ANY().getCode(), buf.readUint16());
+    // TTL is a 32-but value, expecting 0
+    EXPECT_EQ(0, buf.readUint32());
+    // There is no RDATA, so RDLENGTH is 0
+    EXPECT_EQ(0, buf.readUint16());
+
+    // Start checking Update section. This section contains RRset with
+    // one A RR.
+
+    // The name of the RR is 'foo.example.com'. It is encoded in the
+    // compressed format - as a pointer to the name of prerequisite 1.
+    // This name is in offset 0x1D in this message.
+    EXPECT_EQ(0xC01D, buf.readUint16());
+    // TYPE is A
+    EXPECT_EQ(RRType::A().getCode(), buf.readUint16());
+    // CLASS is IN (same as zone class)
+    EXPECT_EQ(RRClass::IN().getCode(), buf.readUint16());
+    // TTL is a 32-but value, set here to 10.
+    EXPECT_EQ(10, buf.readUint32());
+    // For A records, the RDATA comprises the 4-byte Internet address.
+    // So, RDLENGTH is 4.
+    EXPECT_EQ(4, buf.readUint16());
+    // We have stored the following address in RDATA field: 10.10.1.1
+    // (which is 0A 0A 01 01) in hexadecimal format.
+    EXPECT_EQ(0x0A0A0101, buf.readUint32());
+
+    // @todo: consider extending this test to verify Additional Data
+    // section.
 }
 
 } // End of anonymous namespace