Question

I am working on some specs for my Rails app that involve re-ordering Models in the database.

Since the Model IDs are not known ahead of time, I don’t want to hard-code the “List of Model IDs should be [1,2,3]”, so I simply collect them in an array as I create them, e.g.

(1..3).each
  ids << Model.create().id

Model.find(:all, order: position).should == ids

Anyway, I want to test my reorder logic that takes a list of ordered IDs:

Model.reorder( [3,1,2] ) # will change position in db 

to keep things DRY I just do:

reordered_ids = [ids[3], ids[1], ids[2]]
Model.reorder( reordered_ids )

Model.find(...).should == reordered_ids

I was curious if there’s a more elegant way to doing

reordered_ids = [ids[3], ids[1], ids[2]]

This works but doesn’t seem better:

[3,1,2].collect{|i| ids[i] }

Any thoughts?

Answer 1

reordered_ids = [ids[3], ids[1], ids[2]]

reordered_ids = ids.values_at(3, 1, 2)

(1..3).each ids << Model.create().id

ids = 3.times.map { Model.create.id }