date_parse_spec.rb

require 'rubygems'
require 'rspec'
require 'date'
require 'time'

module MyHelper
  extend self
  
  def convert_to_datetime(input)
    if input.is_a?(String)
      DateTime.parse(input)
    else
      input
    end
  end
end

describe MyHelper do
  describe 'convert_to_datetime functionality' do

    let(:input) { '2012-03-04' }
    let(:date_version) { DateTime.parse(input) }

    it 'should successfully convert a well formatted date string' do
      output = MyHelper.convert_to_datetime input
      output.should be_an_instance_of(DateTime)
      output.should == date_version
    end

    it 'should return the original date if a DateTime object was passed in' do
      output = MyHelper.convert_to_datetime date_version
      output.should be_an_instance_of(DateTime)
      output.should == date_version
    end
  end
end

# > rspec -v
#2.14.2
#
#> rspec delete_spec.rb
#..
#
#Finished in 0.00097 seconds
#2 examples, 0 failures