public async Task ModifyRankAsync_ItemFound_SuccessfullyUpdatesRank() { // Arrange var user = new IdentityUser("user_1") { Id = Guid.NewGuid().ToString(), }; _context.Users.Add(user); var item = new TodoItem(42, user.Id, "Fresh item", Importance.High) { Rank = 1, }; _context.TodoItems.Add(item); int newRank = item.Rank + 5; await _context.SaveChangesAsync(); // Act await _todoItemRepository.ModifyRankAsync(item.TodoItemId, newRank); // Assert TodoItem afterUpdate = await _context.TodoItems.SingleAsync(i => i.TodoItemId == item.TodoItemId); Assert.Equal(newRank, afterUpdate.Rank); }