Is it important to unit test a constructor?

Question

Ought I to unit test constructors? Say I have a constructor like this:

IMapinfoWrapper wrapper;
public SystemInfo(IMapinfoWrapper mapinfoWrapper)
{
    this.         


        

Answer 1

You absolutely should test the constructor. If you have a default constructor, you should test that it can be called. What if later on the class is changed--perhaps it becomes a singleton or the default constructor is removed in favor of one requiring parameters? The test should fail in that case to alert that change (so that the class or the test can be fixed to meet the new requirement).

The presence of a default constructor is a requirement that should have a test. Even if all the constructor does is set private members that will be tested elsewhere, the fact that there is a parameterless constructor should be tested.