public void CreatesCorrectUrlWithRepositoryId()
            {
                var gitHubClient = Substitute.For <IGitHubClient>();
                var client       = new ObservableIssuesLabelsClient(gitHubClient);

                var newLabel = new NewLabel("labelName", "FF0000");

                client.Create(1, newLabel);

                gitHubClient.Received().Issue.Labels.Create(1, newLabel);
            }
            public async Task EnsuresNonNullArguments()
            {
                var client   = new ObservableIssuesLabelsClient(Substitute.For <IGitHubClient>());
                var newLabel = new NewLabel("labelName", "FF0000");

                Assert.Throws <ArgumentNullException>(() => client.Create(null, "name", newLabel));
                Assert.Throws <ArgumentNullException>(() => client.Create("owner", null, newLabel));
                Assert.Throws <ArgumentNullException>(() => client.Create("owner", "name", null));

                Assert.Throws <ArgumentNullException>(() => client.Create(1, null));

                Assert.Throws <ArgumentException>(() => client.Create("", "name", newLabel));
                Assert.Throws <ArgumentException>(() => client.Create("owner", "", newLabel));
            }