From: Gavin Sinclair <gsinclair@...>
Date: 2004-05-18T08:06:29+09:00
Subject: Re: How to duck type? - the psychology of static typing in Ruby

On Monday, May 17, 2004, 11:52:22 PM, Tim wrote:

> Now if you'd been writing and collecting unit tests as you went along,
> instead of

>    NoMethodError: undefined method `year' for "notadate":String

> you would be seeing

>    1) Failure:
> test_stuff(MyClassTest) [./test/myclasstest.rb:13]:
> <false> is not true.

> which makes the error even easier to find: you go to test/myclasstest.rb
> and see something like:

> 10:  def test_date
> 11:    @obj = Foo.new
> 12:    @obj.date = MyClass.new.notadate
> 13:    assert(@obj.date.respond_to?(:year))
> 14:  end


Now I'm no unit testing guru (I try...) but that test to me seems so
trivial as to be pointless.  Since the code it's testing does
absolutely nothing other than assignment, you're not testing the
*code*, you're testing one possible input value.

I think it would be more convincing to talk about unit tests covering
the correct overall operation of the class under scrutiny, rather than
examining some lowly accessor.

# But your psychological needs could differ from mine :)

The rest of the article's good, though.

Cheers,
Gavin