diff --git a/Octokit.Tests/Models/PunchCardTests.cs b/Octokit.Tests/Models/PunchCardTests.cs
index c46baf0e..05f6f19e 100644
--- a/Octokit.Tests/Models/PunchCardTests.cs
+++ b/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>);
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/Octokit.Tests/Models/SearchCodeRequestTests.cs b/Octokit.Tests/Models/SearchCodeRequestTests.cs
new file mode 100644
index 00000000..7035c6e4
--- /dev/null
+++ b/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>);
+        }
+    }
+}
diff --git a/Octokit.Tests/Models/SearchIssuesRequestTests.cs b/Octokit.Tests/Models/SearchIssuesRequestTests.cs
new file mode 100644
index 00000000..b26d343c
--- /dev/null
+++ b/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>);
+        }
+    }
+}
diff --git a/Octokit.Tests/Models/SearchUsersRequestTests.cs b/Octokit.Tests/Models/SearchUsersRequestTests.cs
new file mode 100644
index 00000000..7a6a3a39
--- /dev/null
+++ b/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>);
+        }
+    }
+}
diff --git a/Octokit.Tests/Octokit.Tests.csproj b/Octokit.Tests/Octokit.Tests.csproj
index d60624e7..a2dd679f 100644
--- a/Octokit.Tests/Octokit.Tests.csproj
+++ b/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" />
diff --git a/Octokit/Models/Request/SearchCodeRequest.cs b/Octokit/Models/Request/SearchCodeRequest.cs
index 4a55d60e..baacdc58 100644
--- a/Octokit/Models/Request/SearchCodeRequest.cs
+++ b/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
diff --git a/Octokit/Models/Request/SearchIssuesRequest.cs b/Octokit/Models/Request/SearchIssuesRequest.cs
index 2bcdaace..37e1ec9e 100644
--- a/Octokit/Models/Request/SearchIssuesRequest.cs
+++ b/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
diff --git a/Octokit/Models/Response/PunchCard.cs b/Octokit/Models/Response/PunchCard.cs
index ef2a7e9d..7180478d 100644
--- a/Octokit/Models/Response/PunchCard.cs
+++ b/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>