network: Add a function to test header (de)serialization

doc/manual/source/how-to-write-tests.rst

@@ -214,6 +214,41 @@ keep up-to-date.  Output as little as needed for the example and
 include only behavioral state that is important for determining if the
 example has run correctly.
 
+Testing (de)serialization of Headers
+************************************
+Implementing serialization and deserialization of Headers is often prone to
+errors. A generic approach to test these operations is to start from a given
+Header, serialize the given header in a buffer, then create a new header by
+deserializing from the buffer and serialize the new header into a second buffer.
+If everything is correct, the two buffers have the same size and the same content.
+
+The ``HeaderSerializationTestCase`` class enables to perform such a test in an
+easy manner. Test cases willing to exploit such an approach have to inherit from
+``HeaderSerializationTestCase`` instead of ``TestCase`` and pass a Header object
+to the ``TestHeaderSerialization`` method (along with arguments that may be
+needed to construct the new header that is going to be deserialized).
+
+Note that such an approach is not restricted to Header subclasses, but it is
+available for all classes that provide (de)serialization operations, such as
+the wifi Information Elements.
+
+::
+
+   #include "ns3/header-serialization-test.h"
+   class BasicMultiLinkElementTest : public HeaderSerializationTestCase
+   {
+     ...
+   };
+   void
+   BasicMultiLinkElementTest::DoRun (void)
+   {
+     MultiLinkElement mle (WIFI_MAC_MGT_BEACON);
+     // Fill in the Multi-Link Element
+     TestHeaderSerialization (mle, WIFI_MAC_MGT_BEACON);
+   }
+
+Examples of this approach are found, e.g., in ``src/wifi/test/wifi-eht-info-elems-test.cc``
+
 Testing for boolean outcomes
 ****************************
 

src/network/CMakeLists.txt

@@ -98,6 +98,7 @@ set(header_files
     model/tag-buffer.h
     model/tag.h
     model/trailer.h
+    test/header-serialization-test.h
     utils/address-utils.h
     utils/bit-deserializer.h
     utils/bit-serializer.h

src/network/test/header-serialization-test.h

@@ -0,0 +1,98 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2022 Universita' degli Studi di Napoli Federico II
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Authors: Davide Magrin <magrin.davide@gmail.com>
+ *          Stefano Avallone <stavallo@unina.it>
+ */
+
+#ifndef NS3_TEST_HDR_SERIALIZE_H
+#define NS3_TEST_HDR_SERIALIZE_H
+
+#include "ns3/buffer.h"
+#include "ns3/test.h"
+
+namespace ns3 {
+
+/**
+ * Subclass of TestCase class adding the ability to test the serialization and
+ * deserialization of a Header object.
+ */
+class HeaderSerializationTestCase : public TestCase
+{
+protected:
+  /**
+   * \brief Constructor.
+   *
+   * \param [in] name The name of the new TestCase created
+   */
+  HeaderSerializationTestCase (std::string name)
+    : TestCase (name) {}
+
+public:
+  /**
+   * Serialize the given header in a buffer, then create a new header by
+   * deserializing from the buffer and serialize the new header into a new buffer.
+   * Verify that the two buffers have the same size and the same content.
+   *
+   * \tparam T \deduced Type of the given header
+   * \tparam Args \deduced Type of arguments to pass to the constructor of the header
+   * \param [in] hdr the header to test
+   * \param [in] args the arguments to construct the new header
+   */
+  template <typename T, typename... Args>
+  void TestHeaderSerialization (const T& hdr, Args&&... args);
+};
+
+} //namespace ns3
+
+/***************************************************************
+ *  Implementation of the templates declared above.
+ ***************************************************************/
+
+namespace ns3 {
+
+template <typename T, typename... Args>
+void
+HeaderSerializationTestCase::TestHeaderSerialization (const T& hdr, Args&&... args)
+{
+  Buffer buffer;
+  buffer.AddAtStart (hdr.GetSerializedSize ());
+  hdr.Serialize (buffer.Begin ());
+
+  T otherHdr (std::forward<Args> (args)...);
+  otherHdr.Deserialize (buffer.Begin ());
+  Buffer otherBuffer;
+  otherBuffer.AddAtStart (otherHdr.GetSerializedSize ());
+  otherHdr.Serialize (otherBuffer.Begin ());
+
+  NS_TEST_ASSERT_MSG_EQ (buffer.GetSize (), otherBuffer.GetSize (), "Size of buffers differs");
+
+  Buffer::Iterator bufferIterator = buffer.Begin ();
+  Buffer::Iterator otherBufferIterator = otherBuffer.Begin ();
+  for (uint32_t j = 0; j < buffer.GetSize (); j++)
+    {
+      uint8_t bufferVal = bufferIterator.ReadU8 ();
+      uint8_t otherBufferVal = otherBufferIterator.ReadU8 ();
+      NS_TEST_EXPECT_MSG_EQ (+bufferVal, +otherBufferVal,
+                             "Serialization -> Deserialization -> Serialization "
+                             << "is different than Serialization at byte " << j);
+    }
+}
+
+} // namespace ns3
+
+#endif /* NS3_TEST_HDR_SERIALIZE_H */