public void AddMoreCopiesOfBook_AddOneBookToEmptyList_ReturnCountNrOne() { ////Arrange var options = new DbContextOptionsBuilder <ApplicationDbContext>() .UseInMemoryDatabase("MDLibrary_AddMoreCopies") .Options; var context = new ApplicationDbContext(options); var expectedResult = 1; var testBook = new BookCopy() { ID = 1, BookDetailsID = 2 }; var testBookService = new BookServices(context); //Act testBookService.AddMoreCopiesOfBook(testBook); var actualResult = context.BookCopy.ToList().Count; //Assert Assert.Equal(expectedResult, actualResult); }