Class method outputs string message, can't unit test due error citing conversion from void to string not applicable

user_8633966 0
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I'm quite new to unit testing. So far, I'm able to successfully unit test methods that return a data type, such as enum types, integer types, and string types. However, I can't seem to unit test void return type methods that outputs a string, it says unable to convert 'void' to string. There isn't a return type. The code below should clarify my problem. This is the method:

public void Details()
    {
        if (_type == AccountType.FixedDeposit)
        {
            Console.WriteLine(String.Format("Fixed Deposit Account:{0,-5}Balance:{1}", _accNumber, _balance));
        }
        else
        {
            Console.WriteLine(String.Format("{0,-13} Account:{1,-5}Balance:{2}", _type, _accNumber, _balance));
        }

This is the unit test code:

[TestCase]
    public void TestDetails()
    {
        BankAccount b = new BankAccount(111, AccountType.Saving);
        b.Deposit(1000);
        b.Withdraw(500);
        StringAssert.AreEqualIgnoringCase("Saving       Account:111  Balance:500", b.Details());
    }

I expected it to output a string that is able to compare too.

compiler-errors unit-testing c#
1 Answers

Change Details to return the string instead of printing it out:

public string Details()
{
    if (_type == AccountType.FixedDeposit)
    {
        return String.Format("Fixed Deposit Account:{0,-5}Balance:{1}", _accNumber, _balance);
    }
    else
    {
        return String.Format("{0,-13} Account:{1,-5}Balance:{2}", _type, _accNumber, _balance);
    }
}

Note that you'll have to change your "production" code and add the Console.WriteLine calls to the places that called Details.

user_24227760
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