failing test: TeamClient.AddMembership(..) using a real ApiConnection…

… throws an ArgumentNullExceptionValue

Octokit.Tests/Clients/TeamsClientTests.cs

@@ -8,7 +8,7 @@
 namespace Octokit.Tests.Clients
 {
     /// <summary>
-    /// Client tests mostly just need to make sure they call the IApiConnection with the correct 
+    /// Client tests mostly just need to make sure they call the IApiConnection with the correct
     /// relative Uri. No need to fake up the response. All *those* tests are in ApiConnectionTests.cs.
     /// </summary>
     public class TeamsClientTests
@@ -152,6 +152,22 @@ public async Task RequestsTheCorrectUrl()
                     Args.Object);
             }
 
+            [Fact]
+            public async void DoesNotFailWithAnArgumentNullExceptionValue()
+            {
+                var connection = Substitute.For<IConnection>();
+
+                var apiConnection = new ApiConnection(connection);
+
+                var client = new TeamsClient(apiConnection);
+
+                await client.AddMembership(1, "user");
+
+                connection.Received().Put<Dictionary<string, string>>(
+                    Arg.Is<Uri>(u => u.ToString() == "teams/1/memberships/user"),
+                    Arg.Is<string>(u => u == null));
+            }
+
             [Fact]
             public async Task EnsuresNonNullOrEmptyLogin()
             {