[geos-devel] Using static values in Unit Tests

[Mateusz Łoskot]

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