After running the automated tests generated by Pex, it’s amazing how many functions in the old codebase received various class or structure arguments and immediately started working with the data in them without ever checking for null. It was a paradigm followed by the old public code release of Diku, Envy, Merc, etc. and was unthinkingly carried on by the Basternae 2 programmers, myself included. This lack of data validation is being corrected.

It’s no surprise that the old codebase crashed a lot. After seeing the extent of the damage, I feel like I need to go back and revisit the Magma codebase and add a lot of stabilization.

In fact, one of the main things with Basternae 3 that will help stability is the fact that all player-entered commands are executed within a try-catch block. This means that typing in a broken or unsupported command should never crash the MUD, which was a huge problem in the “bad old days”. Instead it will log an error and appear to do absolutely nothing from the player’s viewpoint.

In general either code works or it doesn’t and it’s easy to tell whether it does or doesn’t work. At least until you reach a certain level of complexity. At some point a project gets large enough that you can’t tell which project/dll your error is coming from, let alone which of the 100K or even 50M lines of code is doing naughty things.

Today I had a problem that was easier to solve by creating unit tests to point out where the flaw was. The tool uset? MbUnit.

Here’s an example of an MbUnit test I wrote in order to find a string processing bug:


using System;
using System.Collections.Generic;
using System.Text;
using MbUnit.Framework;
namespace UnitTests
{
[TestFixture]
public class MUDStringTests
{
[RowTest]
[Row(12, "12.box", "box")]
[Row(1, "cheese", "cheese")]
[Row(1, "1.pie", "pie")]
[Row(1, ".chicken", "chicken")]
public void NumberArgument(int expectedValue, string inputString, string expectedOutput)
{
string str = String.Empty;
Assert.AreEqual(expectedValue, BasternaeMud.MUDString.NumberArgument(inputString, ref str));
Assert.AreEqual(expectedOutput, str);
}
}
}

What this does is check whether we’re getting the expected output when we give a certain piece of input. It’s handy for detecting anomalies without having to boot up the server and/or mess with production code. Mind you, there’s no such thing as ‘production code’ since we don’t have a server up yet, but this sort of thing is likely to be handy in the future.

I’m not the type that has any chance of turning into a ‘write the unit tests first’ and ‘unit tests are more important than code’ evangelistic freak, but in most cases it is far easier than using trial-and-error to track down a bug.

I still hate the way WordPress formats my code.