public async Task FindDebtorsAsync_WhenContactAccountCollectionIsEmpty_ReturnsCalculatedAccountCollection()
        {
            IContactAccountCollection sut = CreateSut();

            DateTime statusDate = DateTime.Now.AddDays(_random.Next(1, 365) * -1);
            IContactAccountCollection result = await(await sut.CalculateAsync(statusDate)).FindDebtorsAsync();

            Assert.That(result.StatusDate, Is.EqualTo(statusDate.Date));
        }
        public async Task FindDebtorsAsync_WhenContactAccountCollectionContainsContactAccounts_ReturnsCalculatedAccountCollection()
        {
            IContactAccountCollection sut = CreateSut();

            IEnumerable <IContactAccount> contactAccountCollection = new List <IContactAccount>
            {
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object,
                _fixture.BuildContactAccountMock(contactAccountType: _random.Next(100) > 50 ? ContactAccountType.Debtor : ContactAccountType.Creditor).Object
            };

            sut.Add(contactAccountCollection);

            DateTime statusDate = DateTime.Now.AddDays(_random.Next(1, 365) * -1);
            IContactAccountCollection result = await(await sut.CalculateAsync(statusDate)).FindDebtorsAsync();

            Assert.That(result.StatusDate, Is.EqualTo(statusDate.Date));
        }