public async void GetByGenreAsync(string idGenre, int PageSize, int PageNumber)
{
IEnumerable <Track> track = new List <Track> ();
_trackRepositoryMock.Setup(r => r.GetByGenreAsync(idGenre, PageSize, PageNumber)).Returns(Task.FromResult(track));
var result = await _trackService.GetByGenreAsync(idGenre, PageSize, PageNumber);
Assert.NotNull(result);
_trackRepositoryMock.Verify(x => x.GetByGenreAsync(idGenre, PageSize, PageNumber), Times.Once());
}