[vtk-developers] Comparing ascii files with kwsys::FilesDiffer

[Bill Lorensen]

The files in question are ASCII files, not baseline images.

On Fri, Feb 8, 2013 at 3:31 PM, Brad King <brad.king at kitware.com> wrote:
> On 02/08/2013 03:26 PM, Bill Lorensen wrote:
>> The test compares two ASCII files. The difference is because (some,
>> but not all) windows systems handle newline differently than linux and
>> mac os.
>
> The SystemTools::FilesDiffer method was originally added for CMake's
> configure_file command to decide whether to replace a file with a new
> version or to not replace it because the configured result is the same.
> In this use case both files are produced the same way so newlines match.
> That's why we haven't covered this before.
>
>> In the link you can see that the contents of the two files "look" the
>> same, but the lengths of the two files is different and
>> vtksys::FilesDiffer reports they are different. That's because some
>> windows systems use a CR/LF character for newline while the linux
>> systems use LF.
>>
>> How to solve this? I could add a FileDiff program to the test that
>> uses getline to compare the two files.
>
> We don't use FilesDiffer to compare test images to baselines because
> there can be pixel-fuzz differences and such.  Text file comparison
> may have various tolerances other than just newlines and we will not
> be able to cover them all in FilesDiffer.  Therefore I think VTK
> should have its own comparison tool for text files just like it does
> for images.
>
> -Brad



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