Re: [rails-oceania] How do you spec sorting?

[David Goodlad]

On 14/08/2012, at 2:02 PM, Dmytrii Nagirniak <dna...@gmail.com> wrote:

> I wonder what approaches you take to spec-ing ordering.
> Often the ordering doesn't matter much and I tend to skip that part.
> 
> But when it is a feature and doesn't map directly to SQLs "ORDER BY" clause 
> then it must be spec-ed.
> This is especially the case when a mix of DB sorting + memory sorting should 
> be applied.

Hi Dmytrii

It depends on what kind of ordering you're talking about. If you're ordering 
after-the-fact, post-SQL query, you could extract your ordering logic into a 
class that orders "things" given to it in a specific way:

class OrderedFooList
  include Enumerable

  def initialise(foos)
    @foos = foos
  end

  def ordered
    @ordered ||= order(@foos)
  end

  def order
    @foos.sort_by { |foo| foo.name.to_lower }
  end

  def each(&block)
    ordered.each(&block)
  end
end

describe OrderedFooList
  let(:shorts) { stub(:name => "Shorts") }
  let(:socks) { stub(:name => "socks") }

  let(:foos) { [socks, shorts] }

  subject { OrderedFooList.new(foos) }

  it "should order by lowercase name" do
    subject.to_a.should == [shorts, socks]
  end
end

I'm unsure if this is overkill or over-engineered for your needs, but from your 
message it did sound like you were trying to do something more than a simple 
MyActiveRecordModel.order("name ASC").all.

Dave

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