Why we test the simple stuff ...

One of the more popular arguments trotted out when you're trying to persuade somebody to give TDD a go is that the really simple stuff doesn't need testing. I can sometimes almost be persuaded that simple getters don't need testing, but frankly, if you don't have a test to drive them out (directly or indirectly) why are you implementing them at all? The fallacy that there is stuff so simple you don't need to bother testing it, because it's so trivial that nobody could possibly make a mistake doing it is proved wrong on a daily (if not hourly) basis on any project with more than two developers.

We found an interesting cock up this morning, in a class implementing AbstractConfigurationEntry, which I've talked about before. Clearly whoever implemented it (and yes, we know the culprit) forgot completely to write a test for it.

Spot the stupid mistake:

	public class StringArrayConfigurationEntry extends AbstractConfigurationEntry<String[]> {
	public StringArrayConfigurationEntry(String name) {
	super(name);
	}
	@Override
	public boolean invalid(String[] value) {
	return false;
	}
	@SuppressWarnings("unchecked")
	@Override
	protected void loadValueFromProperties(Configuration configuration) throws ConfigurationEntryException {
	List<String> list = configuration.getList(name);
	value = new String[list.size()];
	}
	}

view raw StringArrayConfigurationEntry.java hosted with ❤ by GitHub

Yes, he really did create a new String array and then forget to put any values in it ...

Annoyingly, this is in library code, so took one of our pairs about 30 minutes longer than it should have to track down a bizarrely unexpected NullPointerException. Obviously the problem couldn't be in the library, since that's used all over the place, so they must have been making a stupid mistake themselves, right?

Sort your tests out, or pay for it.