public void IsDebitOrIsCredit()
{
var t = new Transaction(debit: _cashOnHand, credit: _bank, amount: 10M);
Assert.That(t.IsDebitAccount(_cashOnHand), Is.True);
Assert.That(t.IsDebitAccount(_bank), Is.False);
Assert.That(t.IsDebitAccount(_mortgage), Is.False);
Assert.That(t.IsCreditAccount(_cashOnHand), Is.False);
Assert.That(t.IsCreditAccount(_bank), Is.True);
Assert.That(t.IsCreditAccount(_mortgage), Is.False);
}