add reset viewmodel method

Author: paladique

src/GitHub.App/Controllers/UIController.cs

@@ -340,7 +340,7 @@ void ConfigureUIHandlingStates()
                 .PermitDynamic(Trigger.Next, () => Go(Trigger.Next))
                 .PermitDynamic(Trigger.Cancel, () => Go(Trigger.Cancel))
                 .PermitDynamic(Trigger.Finish, () => Go(Trigger.Finish))
-                .OnExit(() => Reset());
+                .OnExit(() => ResetViewModel(UIViewType.PRCreation));
 
             uiStateMachine.Configure(UIViewType.Login)
                 .OnEntry(tr => RunView(UIViewType.Login, CalculateDirection(tr)))
@@ -414,6 +414,16 @@ void ConfigureUIHandlingStates()
                 .Permit(Trigger.Finish, UIViewType.None);
         }
 
+        void ResetViewModel(UIViewType viewType)
+        {
+            var flowList = GetObjectsForFlow(activeFlow);
+            IUIPair pair;
+            if (flowList.TryGetValue(viewType, out pair))
+            {
+                pair.ViewModel.Reset();
+            }
+        }
+
         /// <summary>
         /// Configure all the logical state transitions for each of the
         /// ui flows we support.

src/GitHub.App/ViewModels/PullRequestCreationViewModel.cs

@@ -120,9 +120,6 @@ public PullRequestCreationViewModel(IRepositoryHost repositoryHost, ISimpleRepos
             this.WhenAnyValue(x => x.Initialized, x => x.GitHubRepository, x => x.Description, x => x.IsExecuting)
                 .Select(x => !(x.Item1 && x.Item2 != null && x.Item3 != null && !x.Item4))
                 .Subscribe(x => IsBusy = x);
-
-            CancelCommand.Subscribe(_ => Reset());
-            CreatePullRequest.Subscribe(_ => Reset());
         }
 
         public override void Initialize(ViewWithData data = null)

src/UnitTests/GitHub.App/Controllers/UIControllerTests.cs

@@ -16,6 +16,7 @@
 using System.ComponentModel;
 using System.Collections.ObjectModel;
 using GitHub.App.Factories;
+using System.Linq;
 
 public class UIControllerTests
 {
@@ -636,6 +637,9 @@ public void Flow()
                 Assert.True(uiController.IsStopped);
                 Assert.True(success.HasValue);
                 Assert.False(success);
+
+                var vm = provider.GetExportFactoryProvider().GetViewModel(GitHub.Exports.UIViewType.PRCreation).Value;
+                Assert.Equal(2, vm.ReceivedCalls().Where(x => x.GetMethodInfo().Name == nameof(IViewModel.Reset)).Count());
             }
         }