diff --git a/tests/test/mpi/test_mpi_context.cpp b/tests/test/mpi/test_mpi_context.cpp
index 3bc667877..c2508e602 100644
--- a/tests/test/mpi/test_mpi_context.cpp
+++ b/tests/test/mpi/test_mpi_context.cpp
@@ -108,7 +108,8 @@ TEST_CASE_METHOD(MpiBaseTestFixture, "Check joining world", "[mpi]")
 
     auto chainedMsgs = faabric::util::getChainedFunctions(msgA);
     REQUIRE(chainedMsgs.size() == worldSize - 1);
-    auto msgB = plannerCli.getMessageResult(msgA.appid(), *chainedMsgs.begin(), 500);
+    auto msgB =
+      plannerCli.getMessageResult(msgA.appid(), *chainedMsgs.begin(), 500);
 
     // Create another context and make sure it's not initialised
     MpiContext cB;
diff --git a/tests/test/mpi/test_multiple_mpi_worlds.cpp b/tests/test/mpi/test_multiple_mpi_worlds.cpp
index 9e6d1ca40..70b91be16 100644
--- a/tests/test/mpi/test_multiple_mpi_worlds.cpp
+++ b/tests/test/mpi/test_multiple_mpi_worlds.cpp
@@ -61,6 +61,7 @@ TEST_CASE_METHOD(MpiBaseTestFixture, "Test creating two MPI worlds", "[mpi]")
     int worldSizeA = 3;
     auto reqA = faabric::util::batchExecFactory(userA, funcA, 1);
     auto& msgA = *reqA->mutable_messages(0);
+    msgA.set_ismpi(true);
     msgA.set_mpiworldid(worldIdA);
     msgA.set_mpiworldsize(worldSizeA);
     plannerCli.callFunctions(reqA);
@@ -73,6 +74,7 @@ TEST_CASE_METHOD(MpiBaseTestFixture, "Test creating two MPI worlds", "[mpi]")
     int worldSizeB = 6;
     auto reqB = faabric::util::batchExecFactory(userB, funcB, 1);
     auto& msgB = *reqB->mutable_messages(0);
+    msgB.set_ismpi(true);
     msgB.set_mpiworldid(worldIdB);
     msgB.set_mpiworldsize(worldSizeB);
     plannerCli.callFunctions(reqB);
@@ -90,6 +92,9 @@ TEST_CASE_METHOD(MpiBaseTestFixture, "Test creating two MPI worlds", "[mpi]")
 
     // Check that chained function calls are made as expected
     auto actual = sch.getRecordedMessagesAll();
+    // The first recorded message is sent as part of the test fixture, so we
+    // remove it
+    actual.erase(actual.begin());
     int expectedMsgCount = worldSizeA + worldSizeB;
     REQUIRE(actual.size() == expectedMsgCount);
 
diff --git a/tests/utils/fixtures.h b/tests/utils/fixtures.h
index 968d9ee85..b78dc6c76 100644
--- a/tests/utils/fixtures.h
+++ b/tests/utils/fixtures.h
@@ -515,10 +515,8 @@ class RemoteMpiTestFixture : public MpiBaseTestFixture
         // Set up the other world and add it to the global set of hosts
         faabric::HostResources otherResources;
         otherResources.set_slots(ranksOtherWorld);
-        sch.addHostToGlobalSet(otherHost);
-
-        // Queue the resource response for this other host
-        faabric::scheduler::queueResourceResponse(otherHost, otherResources);
+        sch.addHostToGlobalSet(
+          otherHost, std::make_shared<faabric::HostResources>(otherResources));
     }
 
   protected: