better diagnostics

Octokit.Tests.Conventions/SyncObservableClients.cs

@@ -4,8 +4,10 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reactive;
 using System.Reflection;
+using Octokit.Tests.Helpers;
 using Xunit;
 using Xunit.Extensions;
+using Xunit.Sdk;
 
 namespace Octokit.Tests.Conventions
 {
@@ -14,7 +16,7 @@ namespace Octokit.Tests.Conventions
         [Fact]
         private void CheckObservableClientExample()
         {
-            CheckObservableClients(typeof(IAssigneesClient));
+            CheckObservableClients(typeof(ISearchClient));
         }
 
         [Theory]
@@ -24,12 +26,15 @@ namespace Octokit.Tests.Conventions
             var observableClient = clientInterface.GetObservableClientInterface();
             var mainMethods = clientInterface.GetMethodsOrdered();
             var observableMethods = observableClient.GetMethodsOrdered();
-            Assert.Equal(mainMethods.Length, observableMethods.Length);
+            var mainNames = Array.ConvertAll(mainMethods, m => m.Name);
+            var observableNames = Array.ConvertAll(observableMethods, m => m.Name);
+            AssertEx.Empty(observableNames.Except(mainNames), "Extra observable methods");
+            AssertEx.Empty(mainNames.Except(observableNames), "Missing observable methods");
             int index = 0;
             foreach(var mainMethod in mainMethods)
             {
                 var observableMethod = observableMethods[index];
-                CheckMethod(mainMethod, observableMethod);
+                AssertEx.WithMessage(() => CheckMethod(mainMethod, observableMethod), "Invalid signature for " + observableMethod);
                 index++;
             }
         }

Octokit.Tests.Conventions/TypeExtensions.cs

@@ -68,7 +68,12 @@ namespace Octokit.Tests.Conventions
         {
             var observableClient = typeof(IObservableEventsClient);
             var observableClientName = observableClient.Namespace + "." + ObservablePrefix + type.Name.Substring(RealNameIndex);
-            return observableClient.Assembly.GetType(observableClientName, throwOnError: true);
+            var observableInterface = observableClient.Assembly.GetType(observableClientName);
+            if(observableInterface == null)
+            {
+                throw new Exception("Cannot find observable interface "+observableClientName);
+            }
+            return observableInterface;
         }
 
         public static bool IsTask(this Type type)

Octokit.Tests/Helpers/AssertEx.cs

@@ -1,12 +1,33 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Reflection;
 using System.Threading.Tasks;
 using Xunit;
+using Xunit.Sdk;
 
 namespace Octokit.Tests.Helpers
 {
     public static class AssertEx
     {
+        public static void Empty<T>(IEnumerable<T> actual, string message)
+        {
+            var empty = Enumerable.Empty<T>();
+            WithMessage(() => Assert.Equal(empty, actual.ToArray()), message);
+        }
+
+        public static void WithMessage(Action assert, string message)
+        {
+            try
+            {
+                assert();
+            }
+            catch(AssertException ex)
+            {
+                throw new Exception(message, ex);
+            }
+        }
+
         public static void HasAttribute<TAttribute>(MemberInfo memberInfo, bool inherit = false) where TAttribute : Attribute
         {
             Assert.True(memberInfo.IsDefined(typeof(TAttribute), inherit), memberInfo.ToString() + Environment.NewLine);