Should I make a seperate unit test for a method, if it only modifies the parent state?
- by Dante
Should classes, that modify the state of the parent class, but not itself, be unit tested separately? And by separately, I mean putting the test in the corresponding unit test class, that tests that specific class.
I'm developing a library based on chained methods, that return a new instance of a new type in most cases, where a chained method is called. The returned instances only modify the root parent state, but not itself.
Overly simplified example, to get the point across:
public class BoxedRabbits
{
private readonly Box _box;
public BoxedRabbits(Box box)
{
_box = box;
}
public void SetCount(int count)
{
_box.Items += count;
}
}
public class Box
{
public int Items { get; set; }
public BoxedRabbits AddRabbits()
{
return new BoxedRabbits(this);
}
}
var box = new Box();
box.AddRabbits().SetCount(14);
Say, if I write a unit test under the Box class unit tests:
box.AddRabbits().SetCount(14)
I could effectively say, that I've already tested the BoxedRabbits class as well. Is this the wrong way of approaching this, even though it's far simpler to first write a test for the above call, then to first write a unit test for the BoxedRabbits separately?
