Custom holidays with the holidays gem

gistfile1.yml

---
months:
  0:
  - name: Mardi Gras
    regions: [bank]
    function: easter(year)-47
  11: 
  - name: Black Friday
    week: -1
    regions: [bank]
    wday: 5
tests: |
    {Date.civil(2013,2,12) => 'Mardi Gras', 
     Date.civil(2013,11,29) => 'Black Friday'}.each do |date, name|
      assert_equal name, (Holidays.on(date, :bank)[0] || {})[:name]
    end