diff --git a/Framework/Framework.csproj b/Framework/Framework.csproj
index 39b129911..bedb9f8f2 100644
--- a/Framework/Framework.csproj
+++ b/Framework/Framework.csproj
@@ -114,6 +114,7 @@
+
diff --git a/Framework/Test/DebugTestHost.cs b/Framework/Test/DebugTestHost.cs
new file mode 100644
index 000000000..027243f69
--- /dev/null
+++ b/Framework/Test/DebugTestHost.cs
@@ -0,0 +1,89 @@
+// ----------------------------------------------------------------------------------
+// Copyright Microsoft Corporation
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// ----------------------------------------------------------------------------------
+
+namespace DurableTask.Test
+{
+ using System;
+ using System.Collections.Generic;
+ using System.Linq;
+ using DurableTask.History;
+ using Newtonsoft.Json;
+
+ public class DebugTestHost
+ {
+ NameVersionObjectManager orchestrationObjectManager;
+
+ public DebugTestHost()
+ {
+ this.orchestrationObjectManager = new NameVersionObjectManager();
+ }
+
+ public DebugTestHost AddTaskOrchestrations(params Type[] taskOrchestrationTypes)
+ {
+ foreach (Type type in taskOrchestrationTypes)
+ {
+ ObjectCreator creator = new DefaultObjectCreator(type);
+ this.orchestrationObjectManager.Add(creator);
+ }
+
+ return this;
+ }
+
+ public DebugTestHost AddTaskOrchestrations(params ObjectCreator[] taskOrchestrationCreators)
+ {
+ foreach (ObjectCreator creator in taskOrchestrationCreators)
+ {
+ this.orchestrationObjectManager.Add(creator);
+ }
+
+ return this;
+ }
+
+ public string ReplayOrchestration(Type orchestrationType, string serializedHistoryEvents)
+ {
+ return ReplayOrchestration(
+ NameVersionHelper.GetDefaultName(orchestrationType),
+ NameVersionHelper.GetDefaultVersion(orchestrationType),
+ serializedHistoryEvents);
+ }
+
+ public string ReplayOrchestration(string name, string version, string serializedHistoryEvents)
+ {
+
+ TaskOrchestration taskOrchestration = this.orchestrationObjectManager.GetObject(name, version);
+
+ IList replayEvents = this.DeserializeHistoryEvents(serializedHistoryEvents);
+
+ if (replayEvents.Any(re => re.EventType == EventType.GenericEvent))
+ {
+ throw new InvalidOperationException("Cannot replay with GenericEvent");
+ }
+
+ var runtimeState = new OrchestrationRuntimeState(this.DeserializeHistoryEvents(serializedHistoryEvents));
+
+ TaskOrchestrationExecutor executor = new TaskOrchestrationExecutor(runtimeState, taskOrchestration);
+ return JsonConvert.SerializeObject(executor.Execute(), new JsonSerializerSettings()
+ {
+ TypeNameHandling = TypeNameHandling.All,
+ Formatting = Formatting.Indented
+ });
+ }
+
+ IList DeserializeHistoryEvents(string serializedHistoryEvents)
+ {
+ return JsonConvert.DeserializeObject>(
+ serializedHistoryEvents,
+ new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.All });
+ }
+ }
+}