diff --git a/src/google/protobuf/dynamic_message_unittest.cc b/src/google/protobuf/dynamic_message_unittest.cc
index b899f8a8a0..1912b5c025 100644
--- a/src/google/protobuf/dynamic_message_unittest.cc
+++ b/src/google/protobuf/dynamic_message_unittest.cc
@@ -20,6 +20,7 @@
 #include "google/protobuf/dynamic_message.h"
 
 #include <memory>
+#include <vector>
 
 #include "google/protobuf/descriptor.pb.h"
 #include "google/protobuf/testing/googletest.h"
@@ -29,8 +30,43 @@
 #include "google/protobuf/unittest.pb.h"
 #include "google/protobuf/unittest_no_field_presence.pb.h"
 
+
 namespace google {
 namespace protobuf {
+namespace {
+
+void AddUnittestDescriptors(
+    DescriptorPool& pool, std::vector<const FileDescriptor*>* files = nullptr) {
+  // We want to make sure that DynamicMessage works (particularly with
+  // extensions) even if we use descriptors that are *not* from compiled-in
+  // types, so we make copies of the descriptors for unittest.proto and
+  // unittest_import.proto.
+  FileDescriptorProto unittest_file;
+  FileDescriptorProto unittest_import_file;
+  FileDescriptorProto unittest_import_public_file;
+  FileDescriptorProto unittest_no_field_presence_file;
+
+  unittest::TestAllTypes::descriptor()->file()->CopyTo(&unittest_file);
+  unittest_import::ImportMessage::descriptor()->file()->CopyTo(
+      &unittest_import_file);
+  unittest_import::PublicImportMessage::descriptor()->file()->CopyTo(
+      &unittest_import_public_file);
+  proto2_nofieldpresence_unittest::TestAllTypes::descriptor()->file()->CopyTo(
+      &unittest_no_field_presence_file);
+
+  ASSERT_TRUE(pool.BuildFile(unittest_import_public_file) != nullptr);
+  ASSERT_TRUE(pool.BuildFile(unittest_import_file) != nullptr);
+  ASSERT_TRUE(pool.BuildFile(unittest_file) != nullptr);
+  ASSERT_TRUE(pool.BuildFile(unittest_no_field_presence_file) != nullptr);
+
+  if (files) {
+    files->push_back(pool.FindFileByName(unittest_file.name()));
+    files->push_back(pool.FindFileByName(unittest_import_file.name()));
+    files->push_back(pool.FindFileByName(unittest_import_public_file.name()));
+    files->push_back(
+        pool.FindFileByName(unittest_no_field_presence_file.name()));
+  }
+}
 
 class DynamicMessageTest : public ::testing::TestWithParam<bool> {
  protected:
@@ -50,27 +86,7 @@ class DynamicMessageTest : public ::testing::TestWithParam<bool> {
   DynamicMessageTest() : factory_(&pool_) {}
 
   void SetUp() override {
-    // We want to make sure that DynamicMessage works (particularly with
-    // extensions) even if we use descriptors that are *not* from compiled-in
-    // types, so we make copies of the descriptors for unittest.proto and
-    // unittest_import.proto.
-    FileDescriptorProto unittest_file;
-    FileDescriptorProto unittest_import_file;
-    FileDescriptorProto unittest_import_public_file;
-    FileDescriptorProto unittest_no_field_presence_file;
-
-    unittest::TestAllTypes::descriptor()->file()->CopyTo(&unittest_file);
-    unittest_import::ImportMessage::descriptor()->file()->CopyTo(
-        &unittest_import_file);
-    unittest_import::PublicImportMessage::descriptor()->file()->CopyTo(
-        &unittest_import_public_file);
-    proto2_nofieldpresence_unittest::TestAllTypes::descriptor()->file()->CopyTo(
-        &unittest_no_field_presence_file);
-
-    ASSERT_TRUE(pool_.BuildFile(unittest_import_public_file) != nullptr);
-    ASSERT_TRUE(pool_.BuildFile(unittest_import_file) != nullptr);
-    ASSERT_TRUE(pool_.BuildFile(unittest_file) != nullptr);
-    ASSERT_TRUE(pool_.BuildFile(unittest_no_field_presence_file) != nullptr);
+    AddUnittestDescriptors(pool_);
 
     descriptor_ = pool_.FindMessageTypeByName("protobuf_unittest.TestAllTypes");
     ASSERT_TRUE(descriptor_ != nullptr);
@@ -298,5 +314,7 @@ TEST_F(DynamicMessageTest, Proto3) {
 
 INSTANTIATE_TEST_SUITE_P(UseArena, DynamicMessageTest, ::testing::Bool());
 
+
+}  // namespace
 }  // namespace protobuf
 }  // namespace google