Refactored transport/raw/tests to more cleanly handle access to private members of TCPBase (#33306)

* Refactored TestTCP and TestUDP to simplify them. Pulled out the places where test needs access to private members and put those in a TestAccess class.  Moved TCPBaseTestAccess into an H file so it can be used by other tests in the future.

* Clang formatting.

* Added TCPBaseTestAccess.h to BUILD.gn

* Minor change to fix failing test

* Reordered the includes to match the standard "Related header, C system headers, C++ standard library headers, other libraries' headers, your project's headers"

Author: feasel0

src/inet/TCPEndPoint.h

@@ -38,10 +38,6 @@
 
 namespace chip {
 
-namespace Transport {
-class TCPTest;
-};
-
 namespace Inet {
 
 class TCPTest;
@@ -529,7 +525,6 @@ class DLL_EXPORT TCPEndPoint : public EndPointBasis<TCPEndPoint>
     constexpr static size_t kMaxReceiveMessageSize = System::PacketBuffer::kMaxSizeWithoutReserve;
 
 protected:
-    friend class ::chip::Transport::TCPTest;
     friend class TCPTest;
 
     TCPEndPoint(EndPointManager<TCPEndPoint> & endPointManager) :

src/transport/raw/TCP.h

@@ -41,6 +41,10 @@
 namespace chip {
 namespace Transport {
 
+// Forward declaration of friend class for test access.
+template <size_t kActiveConnectionsSize, size_t kPendingPacketSize>
+class TCPBaseTestAccess;
+
 /** Defines listening parameters for setting up a TCP transport */
 class TcpListenParameters
 {
@@ -200,7 +204,9 @@ class DLL_EXPORT TCPBase : public Base
     void CloseActiveConnections();
 
 private:
-    friend class TCPTest;
+    // Allow tests to access private members.
+    template <size_t kActiveConnectionsSize, size_t kPendingPacketSize>
+    friend class TCPBaseTestAccess;
 
     /**
      * Allocate an unused connection from the pool
@@ -330,7 +336,6 @@ class TCP : public TCPBase
     ~TCP() override { mPendingPackets.ReleaseAll(); }
 
 private:
-    friend class TCPTest;
     ActiveTCPConnectionState mConnectionsBuffer[kActiveConnectionsSize];
     PoolImpl<PendingPacket, kPendingPacketSize, ObjectPoolMem::kInline, PendingPacketPoolType::Interface> mPendingPackets;
 };

src/transport/raw/tests/BUILD.gn

@@ -49,6 +49,8 @@ chip_test_suite("tests") {
     test_sources += [ "TestTCP.cpp" ]
   }
 
+  sources = [ "TCPBaseTestAccess.h" ]
+
   public_deps = [
     ":helpers",
     "${chip_root}/src/inet/tests:helpers",

src/transport/raw/tests/TCPBaseTestAccess.h

@@ -0,0 +1,49 @@
+/*
+ *
+ *    Copyright (c) 2024 Project CHIP Authors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#pragma once
+
+#if INET_CONFIG_ENABLE_TCP_ENDPOINT
+#include <transport/raw/TCP.h>
+#endif // INET_CONFIG_ENABLE_TCP_ENDPOINT
+
+namespace chip {
+namespace Transport {
+/**
+ * @brief Class acts as an accessor to private members of the TCPBase class without needing to give
+ *        friend access to each individual test.
+ */
+template <size_t kActiveConnectionsSize, size_t kPendingPacketSize>
+class TCPBaseTestAccess
+{
+public:
+    using TCPImpl = Transport::TCP<kActiveConnectionsSize, kPendingPacketSize>;
+
+    static void * FindActiveConnection(TCPImpl & tcp, Transport::PeerAddress & peerAddress)
+    {
+        return tcp.FindActiveConnection(peerAddress);
+    }
+    static Inet::TCPEndPoint * GetEndpoint(void * state) { return static_cast<ActiveTCPConnectionState *>(state)->mEndPoint; }
+
+    static CHIP_ERROR ProcessReceivedBuffer(TCPImpl & tcp, Inet::TCPEndPoint * endPoint, const PeerAddress & peerAddress,
+                                            System::PacketBufferHandle && buffer)
+    {
+        return tcp.ProcessReceivedBuffer(endPoint, peerAddress, std::move(buffer));
+    }
+};
+} // namespace Transport
+} // namespace chip

src/transport/raw/tests/TestMessageHeader.cpp

@@ -23,14 +23,14 @@
  *
  */
 
+#include <gtest/gtest.h>
+
 #include <lib/core/ErrorStr.h>
 #include <lib/support/CHIPMem.h>
 #include <lib/support/CodeUtils.h>
 #include <protocols/Protocols.h>
 #include <transport/raw/MessageHeader.h>
 
-#include <gtest/gtest.h>
-
 namespace {
 
 using namespace chip;

src/transport/raw/tests/TestPeerAddress.cpp

@@ -21,13 +21,13 @@
 #include <stdint.h>
 #include <string.h>
 
+#include <gtest/gtest.h>
+
 #include <inet/IPAddress.h>
 #include <lib/core/DataModelTypes.h>
 #include <lib/core/PeerId.h>
 #include <transport/raw/PeerAddress.h>
 
-#include <gtest/gtest.h>
-
 namespace {
 
 using namespace chip;