Update() public method

Update a pull request for the specified repository.
http://developer.github.com/v3/pulls/#update-a-pull-request
public Update ( long repositoryId, int number, PullRequestUpdate pullRequestUpdate ) : IObservable
repositoryId long The Id of the repository
number int The PullRequest number
pullRequestUpdate PullRequestUpdate An instance describing the changes to make to the PullRequest ///
return IObservable
            public void UpdatesClientRepositoryPullRequest()
            {
                var pullRequestUpdate = new PullRequestUpdate();
                var gitHubClient = Substitute.For<IGitHubClient>();
                var client = new ObservablePullRequestsClient(gitHubClient);

                client.Update("fake", "repo", 42, pullRequestUpdate);

                gitHubClient.Repository.PullRequest.Received().Update("fake", "repo", 42, pullRequestUpdate);
            }
            public async Task EnsuresNonNullArguments()
            {
                var gitHubClient = Substitute.For<IGitHubClient>();
                var client = new ObservablePullRequestsClient(gitHubClient);

                Assert.Throws<ArgumentNullException>(() => client.Update(null, "name", 42, new PullRequestUpdate()));
                Assert.Throws<ArgumentNullException>(() => client.Update("owner", null, 42, new PullRequestUpdate()));
                Assert.Throws<ArgumentNullException>(() => client.Update("owner", "name", 42, null));

                Assert.Throws<ArgumentNullException>(() => client.Update(1, 42, null));

                Assert.Throws<ArgumentException>(() => client.Update("", "name", 42, new PullRequestUpdate()));
                Assert.Throws<ArgumentException>(() => client.Update("owner", "", 42, new PullRequestUpdate()));
            }