public async Task CreateAndSplitBillAsync_WhenGroupHasMembers_ShouldCreateBillWithEqualLoans(decimal total, int userCount)
{
//Arrange
var sutBuilder = new BillServiceSutBuilder();
var group = sutBuilder.CreateGroupWithUsers("Test group", userCount);
var loaner = group.Users.First();
A.CallTo(() => sutBuilder.GroupRepository.GetByIdAsync(group.Id))
.Returns(group);
A.CallTo(() => sutBuilder.BillRepository.AddAsync(A <Bill> ._))
.ReturnsLazily((Bill bill) => bill);
var createNewBill = sutBuilder.CreateNewBill("Test bill", total, group.Id, loaner.Id);
var billService = sutBuilder.CreateSut();
//Act
var resultBill = await billService.CreateAndSplitBillAsync(createNewBill);
//Assert
A.CallTo(() => sutBuilder.BillRepository.AddAsync(A <Bill> ._))
.MustHaveHappenedOnceExactly();
resultBill.Total.ShouldBe(total);
resultBill.Name.ShouldBe(createNewBill.Name);
resultBill.Loaner.ShouldBe(loaner);
resultBill.Loans.Count.ShouldBe(group.Users.Count);
var billLoanees = resultBill.Loans.Select(loan => loan.Loanee);
billLoanees.ShouldBe(group.Users);
var loanTotal = resultBill.Loans.Sum(loan => loan.Amount);
loanTotal.ShouldBe(total);
//Explanation of ToZero: https://docs.microsoft.com/en-us/dotnet/api/system.midpointrounding?view=netcore-3.1#directed-rounding
var expectedAmount = Math.Round(total / userCount, 2, MidpointRounding.ToZero);
resultBill.Loans.ForEach((loan) =>
{
// Allow error of 1 cent
loan.Amount.ShouldBeInRange(expectedAmount, expectedAmount + 0.01M);
});
}
public void CreateAndSplitBillAsync_WhenGroupDoesNotExist_ShouldThrow()
{
//Arrange
var sutBuilder = new BillServiceSutBuilder();
var group = sutBuilder.CreateGroupWithUsers("Test group", 0);
var loaner = sutBuilder.CreateUser();
A.CallTo(() => sutBuilder.GroupRepository.GetByIdAsync(group.Id))
.Returns <Group?>(null);
A.CallTo(() => sutBuilder.BillRepository.AddAsync(A <Bill> ._))
.ReturnsLazily((Bill bill) => bill);
var createNewBill = sutBuilder.CreateNewBill("Test bill", 100, group.Id, loaner.Id);
var billService = sutBuilder.CreateSut();
//Act & Assert
var exception = Assert.ThrowsAsync <NotFoundException>(async() => await billService.CreateAndSplitBillAsync(createNewBill));
exception.Message.ShouldBe($"Group with id {group.Id} does not exist.");
}
public void CreateAndSplitBillAsync_WhenBillPayeeIsNotInGroup_ShouldThrow(decimal total, int userCount)
{
//Arrange
var sutBuilder = new BillServiceSutBuilder();
var group = sutBuilder.CreateGroupWithUsers("Test group", userCount);
var loaner = sutBuilder.CreateUser();
A.CallTo(() => sutBuilder.GroupRepository.GetByIdAsync(group.Id))
.Returns(group);
A.CallTo(() => sutBuilder.BillRepository.AddAsync(A <Bill> ._))
.ReturnsLazily((Bill bill) => bill);
var createNewBill = sutBuilder.CreateNewBill("Test bill", total, group.Id, loaner.Id);
var billService = sutBuilder.CreateSut();
//Act & Aseert
var exception = Assert.ThrowsAsync <NotFoundException>(async() => await billService.CreateAndSplitBillAsync(createNewBill));
exception.Message.ShouldBe($"Payee with id {loaner.Id} does not exist in group.");
}