public async Task RequestsTheCorrectUrlWithRepositoryIdAndApiOptions()
            {
                var connection = Substitute.For <IApiConnection>();
                var client     = new IssueTimelineClient(connection);

                await client.GetAllForIssue(1, 42, new ApiOptions { PageSize = 30 });

                connection.Received().GetAll <TimelineEventInfo>(
                    Arg.Is <Uri>(u => u.ToString() == "repositories/1/issues/42/timeline"),
                    Arg.Any <Dictionary <string, string> >(),
                    "application/vnd.github.mockingbird-preview,application/vnd.github.starfox-preview",
                    Arg.Is <ApiOptions>(ao => ao.PageSize == 30));
            }
            public async Task RequestsTheCorrectUrl()
            {
                var connection = Substitute.For <IApiConnection>();
                var client     = new IssueTimelineClient(connection);

                await client.GetAllForIssue("fake", "repo", 42);

                connection.Received().GetAll <TimelineEventInfo>(
                    Arg.Is <Uri>(u => u.ToString() == "repos/fake/repo/issues/42/timeline"),
                    Arg.Any <Dictionary <string, string> >(),
                    "application/vnd.github.mockingbird-preview,application/vnd.github.starfox-preview",
                    Arg.Any <ApiOptions>());
            }
            public async Task EnsuresNonNullArguments()
            {
                var client = new IssueTimelineClient(Substitute.For<IApiConnection>());

                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetAllForIssue(null, "repo", 42));
                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetAllForIssue("owner", null, 42));
                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetAllForIssue("owner", "repo", 42, null));
                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetAllForIssue(1, 42, null));

                await Assert.ThrowsAsync<ArgumentException>(() => client.GetAllForIssue("", "repo", 42));
                await Assert.ThrowsAsync<ArgumentException>(() => client.GetAllForIssue("owner", "", 42));

            }
            public async Task RequestsTheCorrectUrlWithRepositoryIdAndApiOptions()
            {
                var connection = Substitute.For<IApiConnection>();
                var client = new IssueTimelineClient(connection);

                await client.GetAllForIssue(1, 42, new ApiOptions {PageSize = 30});

                connection.Received().GetAll<TimelineEventInfo>(
                    Arg.Is<Uri>(u => u.ToString() == "repositories/1/issues/42/timeline"),
                    Arg.Any<Dictionary<string, string>>(),
                    "application/vnd.github.mockingbird-preview",
                    Arg.Is<ApiOptions>(ao => ao.PageSize == 30));
            }
            public async Task RequestsTheCorrectUrl()
            {
                var connection = Substitute.For<IApiConnection>();
                var client = new IssueTimelineClient(connection);

                await client.GetAllForIssue("fake", "repo", 42);

                connection.Received().GetAll<TimelineEventInfo>(
                    Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/issues/42/timeline"), 
                    Arg.Any<Dictionary<string, string>>(),
                    "application/vnd.github.mockingbird-preview",
                    Arg.Any<ApiOptions>());
            }
            public async Task EnsuresNonNullArguments()
            {
                var client = new IssueTimelineClient(Substitute.For <IApiConnection>());

                await Assert.ThrowsAsync <ArgumentNullException>(() => client.GetAllForIssue(null, "repo", 42));

                await Assert.ThrowsAsync <ArgumentNullException>(() => client.GetAllForIssue("owner", null, 42));

                await Assert.ThrowsAsync <ArgumentNullException>(() => client.GetAllForIssue("owner", "repo", 42, null));

                await Assert.ThrowsAsync <ArgumentNullException>(() => client.GetAllForIssue(1, 42, null));

                await Assert.ThrowsAsync <ArgumentException>(() => client.GetAllForIssue("", "repo", 42));

                await Assert.ThrowsAsync <ArgumentException>(() => client.GetAllForIssue("owner", "", 42));
            }