Output failure info to textbox

Fixes #11

xunit.runner.wpf/MainWindow.xaml

@@ -201,7 +201,8 @@
                 <GroupBox Header="Output"
                           Margin="3"
                           Grid.Row="2">
-                    <TextBox IsReadOnly="True" />
+                    <TextBox IsReadOnly="True"
+                             Text="{Binding Output}"/>
                 </GroupBox>
             </Grid>
 

xunit.runner.wpf/ViewModel/MainViewModel.cs

@@ -14,6 +14,7 @@ using System.Threading;
 using System.Threading.Tasks;
 using System.Diagnostics;
 using System.IO;
+using System.Text;
 
 namespace xunit.runner.wpf.ViewModel
 {
@@ -134,6 +135,13 @@ namespace xunit.runner.wpf.ViewModel
             set { Set(ref currentRunState, value); }
         }
 
+        private string output = string.Empty;
+        public string Output
+        {
+            get { return output; }
+            set { Set(ref output, value); }
+        }
+
         public string FilterString
         {
             get { return searchQuery.SearchString; }
@@ -295,7 +303,19 @@ namespace xunit.runner.wpf.ViewModel
             {
                 var testCase = testCases.Single(tc => tc.DisplayName == testFailed.TestCase.DisplayName);
                 testCase.State = TestState.Failed;
-                TestFinished?.Invoke(this, TestStateEventArgs.Failed);
+                var resultString = new StringBuilder(testFailed.TestCase.DisplayName);
+                resultString.AppendLine(" FAILED:");
+                for (int i = 0; i < testFailed.ExceptionTypes.Length; i++)
+                {
+                    resultString.AppendLine($"\tException type: '{testFailed.ExceptionTypes[i]}', number: '{i}', parent: '{testFailed.ExceptionParentIndices[i]}'");
+                    resultString.AppendLine($"\tException message:");
+                    resultString.AppendLine(testFailed.Messages[i]);
+                    resultString.AppendLine($"\tException stacktrace");
+                    resultString.AppendLine(testFailed.StackTraces[i]);
+                }
+                resultString.AppendLine();
+
+                TestFinished?.Invoke(this, TestStateEventArgs.Failed(resultString.ToString()));
                 return !isCancelRequested();
             }
 
@@ -390,6 +410,7 @@ namespace xunit.runner.wpf.ViewModel
                 TestsFailed = 0;
                 TestsSkipped = 0;
                 CurrentRunState = TestState.NotRun;
+                Output = string.Empty;
                 await Task.Run(() => RunTestsInBackground());
             }
             catch (Exception ex)
@@ -440,6 +461,7 @@ namespace xunit.runner.wpf.ViewModel
                     break;
                 case TestState.Failed:
                     TestsFailed++;
+                    Output = Output + e.Results;
                     break;
                 case TestState.Skipped:
                     TestsSkipped++;

xunit.runner.wpf/ViewModel/TestStateEventArgs.cs

@@ -4,14 +4,16 @@ namespace xunit.runner.wpf.ViewModel
 {
     public class TestStateEventArgs : EventArgs
     {
-        public static TestStateEventArgs Failed { get; } = new TestStateEventArgs(TestState.Failed);
+        public static TestStateEventArgs Failed(string results) => new TestStateEventArgs(TestState.Failed, results);
         public static TestStateEventArgs Passed { get; } = new TestStateEventArgs(TestState.Passed);
         public static TestStateEventArgs Skipped { get; } = new TestStateEventArgs(TestState.Skipped);
-        private TestStateEventArgs(TestState state)
+        private TestStateEventArgs(TestState state, string results = null)
         {
             this.State = state;
+            this.Results = results;
         }
 
         public TestState State { get; }
+        public string Results { get; }
     }
 }