Test case for constructor as I have to do filter logic

Question

public Myclass {
public Myclass(AnotherClass obj)
{
_key = obj.key;
_ID = obj.ID;
_CandidateMode = obj.CandidateMode;
if(_CandidateMode == obj.CandidateMode.numeric
{
//Dosomething
}
else
{
//Do something with special character.
}
}
}

I have constructor which does some logic and gets data in adds the data list to a method call. Can anyone give some inputs of handling the logic as test case.