public async Task ReturnsNullIfNotFound()
            {
                var userId  = -1;
                var shelves = await ShelvesEndpoint.GetListOfUserShelves(userId);

                Assert.Null(shelves);
            }
            public async Task ReturnsShelves()
            {
                var userId  = 7284465;
                var shelves = await ShelvesEndpoint.GetListOfUserShelves(userId);

                Assert.NotNull(shelves);
                Assert.NotEmpty(shelves.List);
                Assert.True(shelves.Pagination.TotalItems > 0);
            }