public void Or()
{
Result <int, Exception> res1 = new Ok <int, Exception>(1);
Assert.Equal(1, res1.Or(new Ok <int, Exception>(2)).Unwrap());
Assert.Equal(1, res1.Or(new Err <int, Exception>(new Exception("this is test."))).Unwrap());
Result <int, Exception> res2 = new Err <int, Exception>(new Exception("this is test."));
Assert.Equal(2, res2.Or(new Ok <int, Exception>(2)).Unwrap());
Assert.Equal(typeof(Err <int, Exception>), res2.Or(new Err <int, Exception>(new Exception("this is test."))).GetType());
}