[test] add async MPIPack test

dune/common/parallel/test/mpipacktest.cc

@@ -10,7 +10,9 @@
 constexpr int TAG = 42;
 
 #include <iostream>
+#include <map>
 
+#include <dune/common/classname.hh>
 #include <dune/common/parallel/mpihelper.hh>
 #include <dune/common/parallel/mpipack.hh>
 #include <dune/common/test/testsuite.hh>
@@ -47,6 +49,102 @@ auto testSync(Comm comm)
   return suite;
 }
 
+template<typename Comm>
+auto testASync(Comm comm)
+{
+  Dune::TestSuite suite("testASync");
+
+  int rank = comm.rank();
+  // we receive from left and right
+  int src  = (rank - 1 + comm.size()) % comm.size();
+  int dest = (rank + 1) % comm.size();
+
+  using RecvFuture = Dune::MPIFuture<Dune::MPIPack>;
+  using SendFuture = Dune::MPIFuture<Dune::MPIPack>;
+
+  std::map<int, SendFuture> sendFutures;
+  std::map<int, RecvFuture> recvFutures;
+
+  // recv async
+  {
+    const int reserve = 100;
+    auto future = comm.irecv(Dune::MPIPack(comm,reserve), src, TAG);
+    // MPIPack is non-copyable, thus we can't use sendFutures[dest] = ...;
+    recvFutures.emplace(src, std::move(future));
+    // Alternative: sendFutures.insert( std::make_pair(dest, std::move(future)) );
+  }
+  // send async
+  {
+    Dune::MPIPack pack(comm);
+    pack << 3 << comm.rank();
+    pack << std::vector<int>{4711, 42};
+
+    auto future = comm.isend(std::move(pack), dest, TAG);
+    // MPIPack is non-copyable, thus we can't use sendFutures[dest] = ...;
+    sendFutures.emplace(dest, std::move(future));
+    // Alternative: sendFutures.insert( std::make_pair(dest, std::move(future)) );
+  }
+  // recv
+  for (auto & [rank, future] : recvFutures)
+  {
+    Dune::MPIPack pack = future.get();
+    int drei; pack >> drei;
+    int rank_src; pack >> rank_src;
+    std::vector<int> vec;
+    pack >> vec;
+    suite.check(drei==3) << "received wrong value";
+    suite.check(rank_src==rank) << "received wrong value";
+    suite.check(vec.size() == 2) << "vector has wrong size!";
+    suite.check(vec[0] == 4711 && vec[1] == 42) << "vector contains wrong values!";
+  }
+
+  // wait for send operations to finish
+  for (auto & [rank, future] : sendFutures)
+    future.wait();
+
+  return suite;
+}
+
+template<typename Comm>
+auto testASyncVector(Comm comm)
+{
+  Dune::TestSuite suite("testASync");
+
+  int rank = comm.rank();
+  // we receive from left and right
+  int src  = (rank - 1 + comm.size()) % comm.size();
+  int dest = (rank + 1) % comm.size();
+
+  using RecvFuture = Dune::MPIFuture<std::vector<int>>;
+  using SendFuture = Dune::MPIFuture<std::vector<int>>;
+
+  SendFuture sendFuture;
+  RecvFuture recvFuture;
+
+  // recv async
+  {
+    const int reserve = 2; // size on the receiving side...
+    recvFuture = comm.irecv(std::vector<int>(reserve), src, TAG+src);
+  }
+  // send async
+  {
+    std::vector<int> vec{4711, 42}; // we have to keep the vector until send has finished
+    sendFuture = comm.isend(std::move(vec), dest, TAG+rank);
+  }
+  // recv
+  {
+    std::cout << rank << " reading future" << std::endl;
+    std::vector<int> vec = recvFuture.get();
+    std::cout << rank << " done" << std::endl;
+    suite.check(vec.size() == 2) << "vector has wrong size!";
+    suite.check(vec[0] == 4711 && vec[1] == 42) << "vector contains wrong values!";
+  }
+  // wait for send to finish
+  sendFuture.wait();
+
+  return suite;
+}
+
 int main(int argc, char** argv){
   Dune::MPIHelper& helper = Dune::MPIHelper::instance(argc, argv);
   Dune::TestSuite suite;
@@ -54,5 +152,9 @@ int main(int argc, char** argv){
 
   suite.subTest(testSync(comm));
 
+  suite.subTest(testASyncVector(comm));
+
+  suite.subTest(testASync(comm));
+
   return suite.exit();
 }