Create() public method

Creates a new Issue Comment for a specified Issue.
http://developer.github.com/v3/issues/comments/#create-a-comment
public Create ( long repositoryId, int number, string newComment ) : IObservable
repositoryId long The Id of the repository
number int The number of the issue
newComment string The text of the new comment
return IObservable
            public void PostsToCorrectUrlWithRepositoryId()
            {
                const string newComment = "some title";
                var gitHubClient = Substitute.For<IGitHubClient>();
                var client = new ObservableIssueCommentsClient(gitHubClient);

                client.Create(1, 1, newComment);

                gitHubClient.Issue.Comment.Received().Create(1, 1, newComment);
            }
            public async Task EnsuresNonNullArguments()
            {
                var gitHubClient = Substitute.For<IGitHubClient>();
                var client = new ObservableIssueCommentsClient(gitHubClient);

                Assert.Throws<ArgumentNullException>(() => client.Create(null, "name", 1, "x"));
                Assert.Throws<ArgumentNullException>(() => client.Create("owner", null, 1, "x"));
                Assert.Throws<ArgumentNullException>(() => client.Create("owner", "name", 1, null));

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

                Assert.Throws<ArgumentException>(() => client.Create("", "name", 1, "x"));
                Assert.Throws<ArgumentException>(() => client.Create("owner", "", 1, "x"));
            }
            public async Task EnsuresArgumentsNotNull()
            {
                var gitHubClient = Substitute.For<IGitHubClient>();
                var client = new ObservableIssueCommentsClient(gitHubClient);

                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create(null, "name", 1, "title").ToTask());
                await Assert.ThrowsAsync<ArgumentException>(() => client.Create("", "name", 1, "x").ToTask());
                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create("owner", null, 1, "x").ToTask());
                await Assert.ThrowsAsync<ArgumentException>(() => client.Create("owner", "", 1, "x").ToTask());
                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create("owner", "name", 1, null).ToTask());
            }