Updates:
Summary: `Should (Not) Be Equal As Numbers` and `Convert To Number` should
take precision as an optional argument
Status: Started
Owner: pekka.klarck
Comment #6 on issue 109 by pekka.klarck: `Should (Not) Be Equal As Numbers`
and `Convert To Number` should take precision as an optional argument
http://code.google.com/p/robotframework/issues/detail?id=109
I spent a little time studying what is the correct way to compare floating
point numbers and found out that "it depends". Rounding numbers definitely
isn't a good general solution, but simple solutions like `abs(a -b) <
delta` doesn't work much better either. Limitations of various approaches
are explained in this great article:
http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
After thinking about this a little I decided that the simple rounding
solution is adequate for a BuiltIn keyword. I will add a note to the
keyword docs about the limitations and suggest that people who need better
precision can implement their own context sensitive keywords.
I also decided to add same `precision` argument to `Convert To Number`
keyword. This kind of rounding behavior can be useful there alone, and
having rounding in one place eases implementing `Should (Not) Be Equal As
Numbers`.
