public async Task AddAsyncAddsElement()
{
// Arrange
var films = new List <Film>
{
new Film {
Rating = 2
},
new Film {
Rating = 3
}
}.AsQueryable();
var mockSet = new Mock <DbSet <Film> >();
mockSet.As <IQueryable <Film> >().Setup(m => m.Provider).Returns(films.Provider);
mockSet.As <IQueryable <Film> >().Setup(m => m.Expression).Returns(films.Expression);
mockSet.As <IQueryable <Film> >().Setup(m => m.ElementType).Returns(films.ElementType);
mockSet.As <IQueryable <Film> >().Setup(m => m.GetEnumerator()).Returns(films.GetEnumerator());
var film = new Film();
var mockContext = new Mock <CinemaDbContext>();
mockContext.Setup(c => c.Films).Returns(mockSet.Object);
mockContext.Setup(m => m.AddAsync(It.IsAny <Film>(), It.IsAny <CancellationToken>()))
.Returns(new ValueTask <EntityEntry <Film> >(Task.FromResult((EntityEntry <Film>)null)));
var filmBusiness = new FilmBusiness(mockContext.Object);
// Act
await filmBusiness.AddAsync(film);
// Assert
mockSet.Verify(m => m.AddAsync(It.IsAny <Film>(), It.IsAny <CancellationToken>()), Times.Once());
mockContext.Verify(m => m.SaveChangesAsync(It.IsAny <CancellationToken>()), Times.Once());
}