public void MoneyInserted_SingleUserShouldHaveCorrectAmount()
{
string userId = "user789";
decimal expectedAmount = 0;
decimal insertedAmount = 0.50M;
decimal actualAmount;
sodaMachineLogic.MoneyInserted(userId, insertedAmount);
actualAmount = mockDataAccess.UserCreditTotal(userId);
Assert.AreEqual(expectedAmount, actualAmount);
}