finder_shared_example.rb

# This file contains shared examples that helps testing classes that has 
# finder methods (e.g. ActiveRecord model classes).
#
# It accepts :expected, :others and :results params
# passed with let blocks:
# 
# it_behaves_like :finder do
#   let(:results) { ... }
#   let(:expected) { ... }
#   let(:others) { ... }
# end
#
# The exaples checks that all the expected records are returned by the finder
# and none of the others is returned.
#
shared_examples_for :finder do |condition_description, clazz|
  
  @recods_string = clazz.blank? ? "records" : clazz.to_s.tableize
  
  if !condition_description.blank?
    @positive_example_name = "finds #{@records_string} that #{condition_description}"
  else
    @positive_example_name = "finds expected #{@records_string}"
  end
  
  it "#{@positive_example_name}" do
    expect(results).to include(*expected)
  end

  it "does not find others" do
    expect(results).not_to include(*others)
  end
end