Mockito mock with constructor parameter

I am using mockito 1.9.5 and wanting to test a class that looks something like this

class MyClass {

public MyClass(String arg1, String arg2, String arg3) {
 this.arg1 = arg1; this.arg2=arg2;...
}

public executeLogic () {

 if (arg1) {// logic to arg3}
 else if (arg2) {// logic to arg3 }

}

}

I tried to mock it but when i execute the real executeLogic method, it looks for arg1, arg2 and fails. I have tried to spy but the doReturn method executes the real method and fails.

@Test public void testLogic() {

  MyClass mc = Mockito.mock(MyClass.class);
   when(mc.executeLogic()).thenCallRealMethod();

}

Any pointers ?