ARROW-18070: [C++] Invoke google::protobuf::ShutdownProtobufLibrary for substrait tests

cpp/src/arrow/engine/CMakeLists.txt

@@ -72,6 +72,7 @@ add_arrow_test(substrait_test
                substrait/ext_test.cc
                substrait/function_test.cc
                substrait/serde_test.cc
+               substrait/protobuf_test_util.cc
                EXTRA_LINK_LIBS
                ${ARROW_SUBSTRAIT_TEST_LINK_LIBS}
                PREFIX

cpp/src/arrow/engine/substrait/protobuf_test_util.cc

@@ -0,0 +1,42 @@
+// 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 <gtest/gtest.h>
+
+#include <google/protobuf/message_lite.h>
+
+namespace arrow {
+namespace engine {
+
+// A global test "environment", to ensure that the Protobuf API is finalized after
+// running unit tests by invoking google::protobuf::ShutdownProtobufLibrary.
+// This will prevent leaks in valgrind tests because it will delete the global objects
+// that were allocated by the Protocol Buffer library (see
+// "protobuf::ShutdownProtobufLibrary" in
+// https://developers.google.com/protocol-buffers/docs/reference/cpp/google.protobuf.message_lite#ShutdownProtobufLibrary.details)
+
+class ProtobufEnvironment : public ::testing::Environment {
+ public:
+  void SetUp() override { GOOGLE_PROTOBUF_VERIFY_VERSION; }
+  void TearDown() override { google::protobuf::ShutdownProtobufLibrary(); }
+};
+
+::testing::Environment* protobuf_env =
+    ::testing::AddGlobalTestEnvironment(new ProtobufEnvironment);
+
+}  // namespace engine
+}  // namespace arrow