add convention test to ensure all response models have a public parameterless ctor

2 model classes were missing one - technically not needed for these 2 classes due to their api calls being basic data types that then get populated into these objects, but it's easiest to just add them to these 2 classes so the test can pass on all response models

Octokit.Tests.Conventions/Exception/MissingPublicParameterlessCtorException.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace Octokit.Tests.Conventions
+{
+    public class MissingPublicParameterlessCtorException : Exception
+    {
+        public MissingPublicParameterlessCtorException(Type modelType)
+            : base(string.Format("Model type '{0}' is missing a Public Parameterless Constructor required by SimpleJson Deserializer.", modelType.FullName))
+        { }
+    }
+}

Octokit.Tests.Conventions/ModelTests.cs

@@ -37,6 +37,18 @@ namespace Octokit.Tests.Conventions
             }
         }
 
+        [Theory]
+        [MemberData("ResponseModelTypes")]
+        public void AllResponseModelsHavePublicParameterlessCtors(Type modelType)
+        {
+            var ctor = modelType.GetConstructor(Type.EmptyTypes);
+
+            if (ctor == null || !ctor.IsPublic)
+            {
+                throw new MissingPublicParameterlessCtorException(modelType);
+            }
+        }
+
         [Theory]
         [MemberData("ResponseModelTypes")]
         public void ResponseModelsHaveGetterOnlyProperties(Type modelType)

Octokit.Tests.Conventions/Octokit.Tests.Conventions.csproj

@@ -67,6 +67,7 @@
     <Compile Include="Exception\MissingClientConstructorTestClassException.cs" />
     <Compile Include="Exception\MissingClientConstructorTestMethodException.cs" />
     <Compile Include="Exception\MissingDebuggerDisplayAttributeException.cs" />
+    <Compile Include="Exception\MissingPublicParameterlessCtorException.cs" />
     <Compile Include="Exception\MissingDebuggerDisplayPropertyException.cs" />
     <Compile Include="Exception\MutableModelPropertiesException.cs" />
     <Compile Include="Exception\PaginationGetAllMethodNameMismatchException.cs" />

Octokit/Models/Response/PunchCard.cs

@@ -10,6 +10,9 @@ namespace Octokit
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public class PunchCard
     {
+        public PunchCard()
+        { }
+
         public PunchCard(IEnumerable<IList<int>> punchCardData)
         {
             Ensure.ArgumentNotNull(punchCardData, "punchCardData");

Octokit/Models/Response/RepositoryLanguage.cs

@@ -7,6 +7,9 @@ namespace Octokit
     [DebuggerDisplay("{DebuggerDisplay,nq}")]
     public class RepositoryLanguage
     {
+        public RepositoryLanguage()
+        { }
+
         public RepositoryLanguage(string name, long numberOfBytes)
         {
             Name = name;