diff --git a/Octokit.Tests/Clients/RepoCollaboratorsClientTests.cs b/Octokit.Tests/Clients/RepoCollaboratorsClientTests.cs
index 90857331..42bb95eb 100644
--- a/Octokit.Tests/Clients/RepoCollaboratorsClientTests.cs
+++ b/Octokit.Tests/Clients/RepoCollaboratorsClientTests.cs
@@ -32,7 +32,8 @@ namespace Octokit.Tests.Clients
                 var client = new RepoCollaboratorsClient(connection);
 
                 client.GetAll("owner", "test");
-                connection.Received().GetAll<User>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/test/collaborators"), null, "application/vnd.github.ironman-preview+json", Args.ApiOptions);
+
+                connection.Received().GetAll<User>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/test/collaborators"), Args.ApiOptions);
             }
 
             [Fact]
@@ -42,6 +43,7 @@ namespace Octokit.Tests.Clients
                 var client = new RepoCollaboratorsClient(connection);
 
                 client.GetAll(1);
+
                 connection.Received().GetAll<User>(Arg.Is<Uri>(u => u.ToString() == "repositories/1/collaborators"), Args.ApiOptions);
             }
 
@@ -61,7 +63,7 @@ namespace Octokit.Tests.Clients
                 client.GetAll("owner", "test", options);
 
                 connection.Received()
-                    .GetAll<User>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/test/collaborators"), null, "application/vnd.github.ironman-preview+json", options);
+                    .GetAll<User>(Arg.Is<Uri>(u => u.ToString() == "repos/owner/test/collaborators"), options);
             }
 
             [Fact]