[C++] Add test for flatbuffers serialization

cpp/src/arrow/ipc/CMakeLists.txt

@@ -41,6 +41,7 @@ add_arrow_test(feather_test)
 add_arrow_ipc_test(json_simple_test)
 add_arrow_ipc_test(read_write_test)
 add_arrow_ipc_test(tensor_test)
+add_arrow_ipc_test(message_internal_test)
 
 # Headers: top level
 arrow_install_all_headers("arrow/ipc")

cpp/src/arrow/ipc/message_internal_test.cc

@@ -0,0 +1,89 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+#include <flatbuffers/flatbuffers.h>
+#include <gtest/gtest.h>
+#include <memory>
+
+#include "arrow/buffer.h"
+#include "arrow/ipc/dictionary.h"
+#include "arrow/ipc/metadata_internal.h"
+#include "arrow/ipc/options.h"
+#include "arrow/memory_pool.h"
+#include "arrow/testing/gtest_util.h"
+#include "arrow/util/key_value_metadata.h"
+
+namespace arrow {
+
+namespace flatbuf = org::apache::arrow::flatbuf;
+
+namespace ipc {
+namespace internal {
+
+using FBB = flatbuffers::FlatBufferBuilder;
+
+// GH-40361: Test that Flatbuffer serialization matches a known output
+// byte-for-byte.
+//
+// Our Flatbuffers code should not depend on argument evaluation order as it's
+// undefined (https://en.cppreference.com/w/cpp/language/eval_order) and may
+// lead to unnecessary platform- or toolchain-specific differences in
+// serialization.
+TEST(TestMessageInternal, TestByteIdentical) {
+  FBB fbb;
+  flatbuffers::Offset<flatbuf::Schema> fb_schema;
+  DictionaryFieldMapper mapper;
+
+  // Create a simple Schema with just one metadata KVP
+  auto f0 = field("f0", int64());
+  auto f1 = field("f1", int64());
+  std::vector<std::shared_ptr<Field>> fields = {f0, f1};
+  std::shared_ptr<KeyValueMetadata> metadata =
+      KeyValueMetadata::Make({"key_1", "key_2"}, {"key_1_value", "key_2_value"});
+  auto schema = ::arrow::schema({f0}, metadata);
+
+  // Serialize the Schema to a Buffer
+  std::shared_ptr<Buffer> outBuffer;
+  ASSERT_OK(WriteSchemaMessage(*schema, mapper, IpcWriteOptions::Defaults(), &outBuffer));
+
+  // This is example output from macOS+ARM+LLVM
+  const uint8_t len = 228;
+  const uint8_t expected[] = {
+      0x10, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0A, 0x00, 0x0E, 0x00, 0x06, 0x00, 0x05, 0x00,
+      0x08, 0x00, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x01, 0x04, 0x00, 0x10, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x0A, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x04, 0x00, 0x08, 0x00, 0x0A, 0x00,
+      0x00, 0x00, 0x6C, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,
+      0x38, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0xD8, 0xFF, 0xFF, 0xFF, 0x18, 0x00,
+      0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x0B, 0x00, 0x00, 0x00, 0x6B, 0x65, 0x79, 0x5F,
+      0x32, 0x5F, 0x76, 0x61, 0x6C, 0x75, 0x65, 0x00, 0x05, 0x00, 0x00, 0x00, 0x6B, 0x65,
+      0x79, 0x5F, 0x32, 0x00, 0x00, 0x00, 0x08, 0x00, 0x0C, 0x00, 0x04, 0x00, 0x08, 0x00,
+      0x08, 0x00, 0x00, 0x00, 0x18, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x0B, 0x00,
+      0x00, 0x00, 0x6B, 0x65, 0x79, 0x5F, 0x31, 0x5F, 0x76, 0x61, 0x6C, 0x75, 0x65, 0x00,
+      0x05, 0x00, 0x00, 0x00, 0x6B, 0x65, 0x79, 0x5F, 0x31, 0x00, 0x00, 0x00, 0x01, 0x00,
+      0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x10, 0x00, 0x14, 0x00, 0x08, 0x00, 0x06, 0x00,
+      0x07, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x10, 0x00, 0x10, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x01, 0x02, 0x10, 0x00, 0x00, 0x00, 0x1C, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x66, 0x30, 0x00, 0x00, 0x08, 0x00,
+      0x0C, 0x00, 0x08, 0x00, 0x07, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
+      0x40, 0x00, 0x00, 0x00};
+  Buffer expectedBuffer(expected, len);
+
+  ASSERT_TRUE(expectedBuffer.Equals(*outBuffer));
+}
+}  // namespace internal
+}  // namespace ipc
+}  // namespace arrow