diff --git a/quic/test_tools/quic_test_utils.cc b/quic/test_tools/quic_test_utils.cc
index ca89a55..edef5dd 100644
--- a/quic/test_tools/quic_test_utils.cc
+++ b/quic/test_tools/quic_test_utils.cc
@@ -17,9 +17,11 @@
 #include "net/third_party/quiche/src/quic/core/crypto/null_encrypter.h"
 #include "net/third_party/quiche/src/quic/core/crypto/quic_decrypter.h"
 #include "net/third_party/quiche/src/quic/core/crypto/quic_encrypter.h"
+#include "net/third_party/quiche/src/quic/core/quic_buffer_allocator.h"
 #include "net/third_party/quiche/src/quic/core/quic_data_writer.h"
 #include "net/third_party/quiche/src/quic/core/quic_framer.h"
 #include "net/third_party/quiche/src/quic/core/quic_packet_creator.h"
+#include "net/third_party/quiche/src/quic/core/quic_simple_buffer_allocator.h"
 #include "net/third_party/quiche/src/quic/core/quic_utils.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
@@ -1264,5 +1266,12 @@
   return storage->ToSpan();
 }
 
+QuicMemSlice MemSliceFromString(quiche::QuicheStringPiece data) {
+  static SimpleBufferAllocator* allocator = new SimpleBufferAllocator();
+  QuicUniqueBufferPtr buffer = MakeUniqueBuffer(allocator, data.size());
+  memcpy(buffer.get(), data.data(), data.size());
+  return QuicMemSlice(std::move(buffer), data.size());
+}
+
 }  // namespace test
 }  // namespace quic
diff --git a/quic/test_tools/quic_test_utils.h b/quic/test_tools/quic_test_utils.h
index faa505d..15d8111 100644
--- a/quic/test_tools/quic_test_utils.h
+++ b/quic/test_tools/quic_test_utils.h
@@ -1251,6 +1251,10 @@
                           quiche::QuicheStringPiece message_data,
                           QuicMemSliceStorage* storage);
 
+// Creates a MemSlice using a singleton trivial buffer allocator.  Performs a
+// copy.
+QuicMemSlice MemSliceFromString(quiche::QuicheStringPiece data);
+
 // Used to compare ReceivedPacketInfo.
 MATCHER_P(ReceivedPacketInfoEquals, info, "") {
   return info.ToString() == arg.ToString();
diff --git a/quic/test_tools/quic_transport_test_tools.h b/quic/test_tools/quic_transport_test_tools.h
index 9c5cef4..3d521ef 100644
--- a/quic/test_tools/quic_transport_test_tools.h
+++ b/quic/test_tools/quic_transport_test_tools.h
@@ -17,6 +17,7 @@
   MOCK_METHOD0(OnSessionReady, void());
   MOCK_METHOD0(OnIncomingBidirectionalStreamAvailable, void());
   MOCK_METHOD0(OnIncomingUnidirectionalStreamAvailable, void());
+  MOCK_METHOD0(OnIncomingDatagramAvailable, void());
 };
 
 class MockServerVisitor : public QuicTransportServerSession::ServerVisitor {