public async Task ReturnsNullIfNotFound()
            {
                var username = Guid.NewGuid().ToString().Replace("-", string.Empty);
                var user     = await UsersEndpoint.GetByUsername(username);

                Assert.Null(user);
            }
            public async Task ReturnsAUser()
            {
                var username = "******";
                var user     = await UsersEndpoint.GetByUsername(username);

                Assert.NotNull(user);
                Assert.Equal(user.Username, username);
            }