public async Task EnsuresArgumentsNotNull()
            {
                var client = Substitute.For<IGitHubClient>();
                var authEndpoint = new ObservableAuthorizationsClient(client);

                await Assert.ThrowsAsync<ArgumentNullException>(() => authEndpoint.GetAll(null).ToTask());
            }
            public void RequestsCorrectUrlWithApiOption()
            {
                var client = Substitute.For<IGitHubClient>();
                var authEndpoint = new ObservableAuthorizationsClient(client);
                
                authEndpoint.GetAll(ApiOptions.None);

                client.Connection.Received(1).Get<List<Authorization>>(Arg.Is<Uri>(u => u.ToString() == "authorizations"),
                    Arg.Is<Dictionary<string, string>>(dictionary => dictionary.Count == 0), null);
            }