Rails core - Nov 2008 - Making assert_difference's default message more helpful

I like assert_difference, but I find the error messages slightly
unhelpful when I''m verifying more than one thing. Suppose something
should create both a new customer and a question, I could write

assert_difference ''Question.count'' do
  assert_difference ''Customer.count'' do
    ...
  end
end

Unlike a normal assertion the test line causing the failure will be a
few lines down the stack trace so it''s not obvious to me with a quick
glance which of the assertions have failed (although this is fixable
by providing a custom failure message).

I''d rather write

assert_difference [''Question.count'',
''Customer.count''] do
  ...
end

but if a failure occurs here then I genuinely don''t know which
assertion has failed (unless I can remember that ''expected 4 got
3''
must be talking about the customer assertion because I remember the
number of records defined in the fixtures).

It seems to me that this could be made more helpful if the default
error message included the expression being evaluated eg something
along the lines of

Customer.count: expected 4, got 3

Thoughts?

Fred
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On Thu, Nov 27, 2008 at 8:38 AM, Frederick Cheung
<frederick.cheung@gmail.com> wrote:
> but if a failure occurs here then I genuinely don''t know which
> assertion has failed (unless I can remember that ''expected 4 got
3''
> must be talking about the customer assertion because I remember the
> number of records defined in the fixtures).
>
> It seems to me that this could be made more helpful if the default
> error message included the expression being evaluated eg something
> along the lines of
>
> Customer.count: expected 4, got 3
+1!

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On Thu, Nov 27, 2008 at 12:38, Frederick Cheung
<frederick.cheung@gmail.com>wrote:
>
> I like assert_difference, but I find the error messages slightly
> unhelpful when I''m verifying more than one thing.

What about github.com/rails/rails/commit/00e2ba ?

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On Nov 27, 12:01 pm, "Mislav Marohnić"
<mislav.maroh...@gmail.com>
wrote:
> On Thu, Nov 27, 2008 at 12:38, Frederick Cheung
> <frederick.che...@gmail.com>wrote:
>
>
>
> > I like assert_difference, but I find the error messages slightly
> > unhelpful when I''m verifying more than one thing.
>
> What about github.com/rails/rails/commit/00e2ba ?
D''oh - haven''t moved stuff to 2.2 yet and hadn''t
notice that commit.
Sorry for the noise!

Fred
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