Alan Francis wrote:
def task_estimate tasks.sum(:estimate) end
Now, the first assert passes, so I figure I'm using 'sum' properly. The second assert fails saying expected 0, got nil.
There's definitely a bug in Active Record that causes empty sums to be returned as nil rather than 0. The Calculations module casts the nil result to to the column's type, but this casting always returns nil for a nil parameter.
I thought I'd found a bug, in summing a collection with no elements, and right enough there's no test for that in ActiveRecord, but when I do the following in the console:
Story.create.task_estimate
I get 0 as expected. So as best I can tell I get nil when summing an empty association during testing, but not in the console.
That's strange, I always get nil.