Fix MultiBufferEncode test with pool allocator

src/system/SystemPacketBuffer.cpp

@@ -581,7 +581,8 @@ PacketBufferHandle PacketBufferHandle::New(size_t aAvailableSize, uint16_t aRese
 
     if (lAllocSize > PacketBuffer::kMaxAllocSize)
     {
-        ChipLogError(chipSystemLayer, "PacketBuffer: allocation exceeding buffer capacity limits.");
+        ChipLogError(chipSystemLayer, "PacketBuffer: allocation exceeding buffer capacity limits: %lu > %lu",
+                     static_cast<unsigned long>(lAllocSize), static_cast<unsigned long>(PacketBuffer::kMaxAllocSize));
         return PacketBufferHandle();
     }
 

src/system/tests/TestTLVPacketBufferBackingStore.cpp

@@ -162,17 +162,28 @@ TEST_F(TestTLVPacketBufferBackingStore, MultiBufferEncode)
     // Third entry is 1 control byte, 2 length bytes, 2000 bytes of data,
     // for a total of 2009 bytes.
     constexpr size_t totalSize = 2009;
-    EXPECT_EQ(buffer->TotalLength(), totalSize);
-    EXPECT_EQ(buffer->DataLength(), static_cast<size_t>(2));
-    ASSERT_TRUE(buffer->HasChainedBuffer());
-    auto nextBuffer = buffer->Next();
-    EXPECT_EQ(nextBuffer->TotalLength(), totalSize - 2);
-    EXPECT_EQ(nextBuffer->DataLength(), PacketBuffer::kMaxSizeWithoutReserve);
-    ASSERT_TRUE(nextBuffer->HasChainedBuffer());
-    nextBuffer = nextBuffer->Next();
-    EXPECT_EQ(nextBuffer->TotalLength(), nextBuffer->DataLength());
-    EXPECT_EQ(nextBuffer->DataLength(), totalSize - 2 - PacketBuffer::kMaxSizeWithoutReserve);
-    ASSERT_FALSE(nextBuffer->HasChainedBuffer());
+#if CHIP_SYSTEM_PACKETBUFFER_FROM_LWIP_STANDARD_POOL || CHIP_SYSTEM_PACKETBUFFER_FROM_CHIP_POOL
+    // In case of pool allocation, the buffer size is always the maximum size.
+    constexpr size_t bufferSizes[] = { PacketBuffer::kMaxSizeWithoutReserve, totalSize - PacketBuffer::kMaxSizeWithoutReserve };
+#elif CHIP_SYSTEM_PACKETBUFFER_FROM_CHIP_HEAP
+    constexpr size_t bufferSizes[] = { 2, PacketBuffer::kMaxSizeWithoutReserve,
+                                       totalSize - 2 - PacketBuffer::kMaxSizeWithoutReserve };
+#else
+    // Skipping the test for other configurations because the allocation method is unknown.
+    GTEST_SKIP();
+#endif
+    size_t checkedSize = 0;
+    auto bufferTmp     = buffer.Retain();
+    for (const auto size : bufferSizes)
+    {
+        ASSERT_FALSE(bufferTmp.IsNull());
+        EXPECT_EQ(bufferTmp->TotalLength(), totalSize - checkedSize);
+        EXPECT_EQ(bufferTmp->DataLength(), size);
+        bufferTmp = bufferTmp->Next();
+        checkedSize += size;
+    }
+    // There should be no more buffers.
+    ASSERT_TRUE(bufferTmp.IsNull());
 
     // PacketBufferTLVReader cannot handle non-contiguous buffers, and our
     // buffers are too big to stick into a single packet buffer.