unique
A lightweight Ruby gem with zero dependencies that prevents a block from returning the same object twice.
Setup
Add it to your project's Gemfile (preferred) or
$ gem install uniqueUsage
require 'unique'
Unique.next! do
#...
endExample
1.9.3-p551 :001 > Unique.next!{ rand(5) }
=> 0
1.9.3-p551 :002 > Unique.next!{ rand(5) }
=> 4
1.9.3-p551 :003 > Unique.next!{ rand(5) }
=> 1
1.9.3-p551 :004 > Unique.next!{ rand(5) }
=> 2
1.9.3-p551 :005 > Unique.next!{ rand(5) }
=> 3
1.9.3-p551 :006 > Unique.next!{ rand(5) }
Unique::NoUniqueObjects: An unused, unique object could not be found in 4096 tries (["(irb)", 6])
from /home/devbox/code/unique/lib/unique.rb:22:in `block in next!'
from /home/devbox/code/unique/lib/unique.rb:20:in `loop'
from /home/devbox/code/unique/lib/unique.rb:20:in `next!'
from (irb):6
from /home/devbox/.rvm/rubies/ruby-1.9.3-p551/bin/irb:12:in `<main>'
1.9.3-p551 :007 >Config
The maximum number of times the block will be yielded looking for a unique object. Default is 4096.
Unique.max_tries= 10Cleanup
Unique.reset! will clear previous objects and allow them to be used. This is
useful in your test suite's before blocks.
Example
1.9.3-p551 :001 > Unique.next!{ rand(1) }
=> 0
1.9.3-p551 :002 > Unique.next!{ rand(1) }
Unique::NoUniqueObjects: An unused, unique object could not be found in 4096 tries (["(irb)", 2])
from /home/devbox/code/unique/lib/unique.rb:22:in `block in next!'
from /home/devbox/code/unique/lib/unique.rb:20:in `loop'
from /home/devbox/code/unique/lib/unique.rb:20:in `next!'
from (irb):6
from /home/devbox/.rvm/rubies/ruby-1.9.3-p551/bin/irb:12:in `<main>'
1.9.3-p551 :003 > Unique.reset!
=> []
1.9.3-p551 :004 > Unique.next!{ rand(1) }
=> 0