[geos-devel] Using static values in Unit Tests

[strk at refractions.net]

I'd go with a tolerance value, but rather then
set it immediately I'll leave it for later, when
we detect differences. I'd start with a tolerance of 0.

--strk;

On Tue, Apr 04, 2006 at 12:33:19AM +0200, Mateusz Å?oskot wrote:
> Hi,
> 
> Simply question, do you think it is safe to use static values for
> results comparison in Unit Tests.
> In example, I want to test length/area calculations, so I need to
> compare result with some well known value.
> 
> The simplest solution is to use:
> // ...
> const double length = 14.142135623730951;
> 
> line.getLength() == length
> 
> Is this safe regarding double prec. numbers representation
> on different architectures?
> 
> Another option is to to check the closure of expected result.
> A little descriptive example of this concept:
> 
> // value of result returned by getLength or getArea
> double result = 14.13873095113561;
> 
> // well-known and expected result for some test case
> const double expected = 14.142135623730951;
> 
> // Check equality with accuracy of 0.001
> double ab = fabs(result - expected);
> if (ab > 0.001)
>    cout << "EQUAL\n";
> else
>    cout << "NOT EQUAL\n";
> 
> or something similar.
> 
> What approach would you recommend?
> 
> Cheers
> -- 
> Mateusz Łoskot
> http://mateusz.loskot.net
> _______________________________________________
> geos-devel mailing list
> geos-devel at geos.refractions.net
> http://geos.refractions.net/mailman/listinfo/geos-devel

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