Remove WriteBufferMeta from retransmission buffer upon ack

Summary: as title

Reviewed By: mjoras

Differential Revision: D27361934

fbshipit-source-id: 81618c039ff026a8b3dc2caba5ce335ee431e15e

quic/state/stream/test/StreamStateMachineTest.cpp

@@ -829,5 +829,34 @@ TEST_F(QuicUnidirectionalStreamTest, ResetSentInvalidRstStream) {
       QuicTransportException);
 }
 
+TEST_F(QuicOpenStateTest, DSRStreamAcked) {
+  auto conn = createConn();
+  conn->clientConnectionId = getTestConnectionId(0);
+  conn->serverConnectionId = getTestConnectionId(1);
+  auto stream = conn->streamManager->createNextBidirectionalStream().value();
+  writeDataToQuicStream(
+      *stream,
+      folly::IOBuf::copyBuffer("Big ship stucks in small water"),
+      false);
+  writeBufMetaToQuicStream(*stream, BufferMeta(1000), true);
+  auto bufMetaStartingOffset = stream->writeBufMeta.offset;
+  handleStreamWritten(
+      *conn,
+      *stream,
+      bufMetaStartingOffset,
+      300,
+      false,
+      1,
+      PacketNumberSpace::AppData,
+      true);
+  ASSERT_NE(
+      stream->retransmissionBufMetas.end(),
+      stream->retransmissionBufMetas.find(bufMetaStartingOffset));
+  WriteStreamFrame frame(stream->id, bufMetaStartingOffset, 300, false);
+  frame.fromBufMeta = true;
+  sendAckSMHandler(*stream, frame);
+  EXPECT_TRUE(stream->retransmissionBufMetas.empty());
+}
+
 } // namespace test
 } // namespace quic