[Pharo-users] Comparing floats

[stepharo]

Hi

I'm writing a simple converter between Celcius and Farhenheit as an 
example to start programming.


Converter >> convertFarhenheit: anInteger
    ^ ((anInteger - 32) / 1.8)

ConverterTest >> testFToC

    | converter |
    converter := TemperatureConverter new.
    self assert: ((converter convertFarhenheit: 86) = 30.0).
    self assert: ((converter convertFarhenheit: 50) = 10).
    self assert: ((converter convertFarhenheit: 52) = 11.11111111111111)


My problem is with ((converter convertFarhenheit: 52) = 11.11111111111111)

I do not want to have such ugly test.

I tried either to control the output

Converter >> convertFarhenheit: anInteger
    ^ ((anInteger - 32) / 1.8) roundDownTo: 0.1

Not a good idea

Or to compare with closeTo:

    self assert: ((converter convertFarhenheit: 52) closeTo: 11.11)

does not work because we cannot set the precision.

So at ESUG I briefly discuss that with Nicolas Cellier and I need help.

Should I introduce in pharo closeTo:interval:

Any suggestions that a newby can understand is welcome.


Stef