Question/poll stats calculation flawed

[timkurvers]

The current implementation for calculating the percentage for a given option for a question is flawed:

percentage = ( 100 / question.votes.count ) * option.votes.count

This will break when rendering the statistics without any votes cast:

percentage = ( 100 / 0 ) * 0
# => ZeroDivisionError: divided by 0

As soon as the amount of votes surpasses 100 the result is always 0 due to integer division:

percentage = ( 100 / 2 ) * 1
# => 50
percentage = ( 100 / 100 ) * 50
# => 50
percentage = ( 100 / 101 ) * 100
# => 0
percentage = ( 100 / 200 ) * 100
# => 0

The quick'n'dirty fix is:

percentage = (( 100.0 / question.votes.count ) * option.votes.count).round rescue 0

This also applies to polls.

[jgorset]

Nice find, @timkurvers.