Make readonly collections truly readonly

These methods actually returned mutable collections that happen
to implement the readonly interfaces. User could cast them to
the actual type and add things. I'd rather avoid even that
possibility by making these truly return readonly stuff.

Octokit.Tests/Models/PunchCardTests.cs

@@ -1,30 +1,31 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using Octokit.Response;
 using Xunit;
 
-namespace Octokit.Tests.Models
+public class PunchCardTests
 {
-    public class PunchCardTests
+    public class TheConstructor
     {
         [Fact]
         public void ThrowsExceptionWithNullPunchCardPoints()
         {
-            Assert.Throws<ArgumentNullException>(()=>new PunchCard(null));
+            Assert.Throws<ArgumentNullException>(() => new PunchCard(null));
         }
 
         [Fact]
         public void ThrowsExceptionWhenPunchCardPointsHaveIncorrectFormat()
         {
-            IList<int> point1 = new []{1,2,3,4,5,6};
-            IEnumerable<IList<int>> points = new List<IList<int>>{point1};
+            IList<int> point1 = new[] { 1, 2, 3, 4, 5, 6 };
+            IEnumerable<IList<int>> points = new List<IList<int>> { point1 };
             Assert.Throws<ArgumentException>(() => new PunchCard(points));
         }
 
         [Fact]
         public void DoesNotThrowExceptionWhenPunchPointsHaveCorrectFormat()
         {
-            IList<int> point1 = new[] { 1, 2, 3};
+            IList<int> point1 = new[] { 1, 2, 3 };
             IEnumerable<IList<int>> points = new List<IList<int>> { point1 };
             Assert.DoesNotThrow(() => new PunchCard(points));
         }
@@ -35,7 +36,7 @@ namespace Octokit.Tests.Models
             IList<int> point1 = new[] { 1, 0, 3 };
             IList<int> point2 = new[] { 1, 1, 4 };
             IList<int> point3 = new[] { 1, 2, 0 };
-            IEnumerable<IList<int>> points = new List<IList<int>> { point1,point2,point3 };
+            IEnumerable<IList<int>> points = new List<IList<int>> { point1, point2, point3 };
 
             var punchCard = new PunchCard(points);
 
@@ -44,10 +45,23 @@ namespace Octokit.Tests.Models
             var commitsAtMondayAt2Am = punchCard.GetCommitCountFor(DayOfWeek.Monday, 2);
             var commitsAtTuesdayAt2Am = punchCard.GetCommitCountFor(DayOfWeek.Tuesday, 2);
 
-            Assert.Equal(3,commitsAtMondayAt12Am);
+            Assert.Equal(3, commitsAtMondayAt12Am);
             Assert.Equal(4, commitsAtMondayAt1Am);
             Assert.Equal(0, commitsAtMondayAt2Am);
             Assert.Equal(0, commitsAtTuesdayAt2Am);
         }
+
+        [Fact]
+        public void SetsPunchPointsAsReadOnlyDictionary()
+        {
+            IList<int> point1 = new[] { 1, 0, 3 };
+            IList<int> point2 = new[] { 1, 1, 4 };
+            IList<int> point3 = new[] { 1, 2, 0 };
+            IEnumerable<IList<int>> points = new List<IList<int>> { point1, point2, point3 };
+
+            var punchCard = new PunchCard(points);
+
+            Assert.Null(punchCard.PunchPoints as ICollection<PunchCardPoint>);
+        }
     }
-}
+}

Octokit.Tests/Models/SearchCodeRequestTests.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using Octokit;
+using Xunit;
+
+public class SearchCodeRequestTests
+{
+    public class TheMergedQualifiersMethod
+    {
+        [Fact]
+        public void ReturnsAReadOnlyDictionary()
+        {
+            var request = new SearchCodeRequest("test");
+            
+            var result = request.MergedQualifiers();
+
+            // If I can cast this to a writeable collection, then that defeats the purpose of a read only.
+            Assert.Null(result as ICollection<string>);
+        }
+    }
+}

Octokit.Tests/Models/SearchIssuesRequestTests.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using Octokit;
+using Xunit;
+
+internal class SearchIssuesRequestTests
+{
+    public class TheMergedQualifiersMethod
+    {
+        [Fact]
+        public void ReturnsAReadOnlyDictionary()
+        {
+            var request = new SearchIssuesRequest("test");
+
+            var result = request.MergedQualifiers();
+
+            // If I can cast this to a writeable collection, then that defeats the purpose of a read only.
+            Assert.Null(result as ICollection<string>);
+        }
+    }
+}

Octokit.Tests/Models/SearchUsersRequestTests.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using Octokit;
+using Xunit;
+
+internal class SearchUsersRequestTests
+{
+    public class TheMergedQualifiersMethod
+    {
+        [Fact]
+        public void ReturnsAReadOnlyDictionary()
+        {
+            var request = new SearchUsersRequest("test");
+
+            var result = request.MergedQualifiers();
+
+            // If I can cast this to a writeable collection, then that defeats the purpose of a read only.
+            Assert.Null(result as ICollection<string>);
+        }
+    }
+}

Octokit.Tests/Octokit.Tests.csproj

@@ -134,6 +134,9 @@
     <Compile Include="Models\ReadOnlyPagedCollectionTests.cs" />
     <Compile Include="Models\RepositoryUpdateTests.cs" />
     <Compile Include="Models\RequestParametersTests.cs" />
+    <Compile Include="Models\SearchCodeRequestTests.cs" />
+    <Compile Include="Models\SearchUsersRequestTests.cs" />
+    <Compile Include="Models\SearchIssuesRequestTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Helpers\StringExtensionsTests.cs" />
     <Compile Include="Clients\RepositoriesClientTests.cs" />

Octokit/Models/Request/SearchCodeRequest.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
@@ -157,7 +158,7 @@ namespace Octokit
                 parameters.Add(String.Format(CultureInfo.InvariantCulture, "repo:{0}", Repo));
             }
 
-            return parameters;
+            return new ReadOnlyCollection<string>(parameters);
         }
 
         internal string DebuggerDisplay

Octokit/Models/Request/SearchIssuesRequest.cs

@@ -1,4 +1,5 @@
-using System.Diagnostics;
+using System.Collections.ObjectModel;
+using System.Diagnostics;
 using Octokit.Internal;
 using System;
 using System.Collections.Generic;
@@ -259,7 +260,7 @@ namespace Octokit
                 parameters.Add(String.Format(CultureInfo.InvariantCulture, "repo:{0}", Repo));
             }
 
-            return parameters;
+            return new ReadOnlyCollection<string>(parameters);
         }
 
         internal string DebuggerDisplay

Octokit/Models/Response/PunchCard.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
@@ -12,7 +13,8 @@ namespace Octokit.Response
         public PunchCard(IEnumerable<IList<int>> punchCardData)
         {
             Ensure.ArgumentNotNull(punchCardData, "punchCardData");
-            PunchPoints = punchCardData.Select(point => new PunchCardPoint(point)).ToList();
+            PunchPoints = new ReadOnlyCollection<PunchCardPoint>(
+                punchCardData.Select(point => new PunchCardPoint(point)).ToList());
         }
 
         /// <summary>