We will continue to demonstrate testing small, but already we have hit our next example. Playing devil's advocate is a useful technique in many circumstances. The way that we play devil's advocate in TDD is by imagining the simplest, and possibly most erroneous, approach to making the test pass. We want to force the test to make the code right instead of writing the code that we believe to be correct. For instance, in this case the desire is to make the test that was just written pass by adding an Items list. But the test doesn't require that at this point. It only requires that Items exists as a property on the class. There is no designation of a type in the test. So, to play devil's advocate, make the test pass by using Object as the type and setting the Items object to a simple non-null value.
internal class TodoList
{
public object Items { get; } = new object();
public TodoList()
{
}
}Okay, now all the tests pass but that clearly isn't a proper solution. Thinking...