check for DebuggerDisplay on models

Octokit.Tests.Conventions/DebuggerDisplayOnModels.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Diagnostics;
+using System.Linq;
+using Octokit.Tests.Helpers;
+using Xunit;
+using Xunit.Extensions;
+
+namespace Octokit.Tests.Conventions
+{
+    public class DebuggerDisplayOnModels
+    {
+        [Fact]
+        public void CheckModelsForDebuggerDisplayAttributeExample()
+        {
+            CheckModelsForDebuggerDisplayAttribute(typeof(IAuthorizationsClient));
+        }
+
+        [Theory]
+        [ClassData(typeof(ClientInterfaces))]
+        public void CheckModelsForDebuggerDisplayAttribute(Type clientInterface)
+        {
+            var methods = clientInterface.GetMethods();
+            var modelTypes =
+                from modelType in
+                    (from type in (
+                        from method in methods from parameter in method.GetParameters() select parameter.ParameterType
+                        ).Union(
+                        from method in methods select method.ReturnType)
+                    select type.GetTypeInfo().Type)
+                where TypeExtensions.IsModel(modelType)
+                select modelType;
+            foreach(var modelType in modelTypes.Distinct())
+            {
+                AssertEx.HasAttribute<DebuggerDisplayAttribute>(modelType);
+            }
+        }
+    }
+}