oleaut32/tests: added tests for negative fractional variant dates.

[James McKenzie]

  On 10/2/10 7:00 PM, Jeremy Drake wrote:
> On Sat, 2 Oct 2010, James McKenzie wrote:
>
>> Looks like you got 'bit' by the way that a finite storage method mangles
>> floating information.  There was a lengthy discussion on how to 'overcome'
>> this on the Wine-Development list a short while ago.
> No, those tests aleady account for that.
>
> /* When comparing floating point values we cannot expect an exact match
>   * because the rounding errors depend on the exact algorithm.
>   */
> #define EQ_DOUBLE(a,b)     (fabs((a)-(b)) / (1.0+fabs(a)+fabs(b))<  1e-14)
> #define EQ_FLOAT(a,b)      (fabs((a)-(b)) / (1.0+fabs(a)+fabs(b))<  1e-7)
>
>      ok_(__FILE__,line)(r == res&&  (FAILED(r) || EQ_DOUBLE(out, dt)),
>                         "expected %x, %.16g, got %x, %.16g\n", r, dt, res,
> out);
>
>
> My understanding is that that algorithm should work to account for
> floating-point inaccuracies (though technically should be using
> DBL_EPSILON and FLT_EPSILON instead of 1e-X constants, but they're
> probably not portable enough for this project),
>
> I was simply bit by my own stupidity, not running my last changes against
> a Windows OS before sending my patch.  This has been corrected in my try2.
Ok.  I seen that.  However, will this work in Wine as well might come up 
as it has before.

I don't want to raise the 'noise' level and I did not see [try 2] before 
making my comment, but this might be something you want to keep in mind 
for the future.

Also, please be aware that my comment is based on a previous thread, 
which you still might want to visit, in this mailing list/forum.  It may 
save you time and give you something to think about in regards to this 
patch and future patches.

Note:  My comment is not based on actual programming experience using 
the Epsilon features and code, but rather on previous comments.  I'm 
just a simple programmer who tests Wine on the Mac platform.

Since I tend to remove messages as they no longer apply to my personal 
habits, however I did find a pointer to the following document written 
by Bruce Dawson:

http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm

This came from 
http://www.winehq.org/pipermail/wine-devel/2010-July/085089.html

It looks like you read through it, based on a review of the proposed 
patch.  I don't know if this can be applied to the ok() checks though.

James McKenzie