require 'pry'

first = 'FF'
second = 'FB'
third = ''

test = Array.new
test.push('')
test.push('FB')
test.push('FF')
test.push('')
test.push('FB')
test.push('FF')
test.push(first)
test.push(second)
test.push(third)

# custom sort, should return FF < FB < ''

puts test.sort do |left,right|
  if left == first && right == second
    -1
  elsif left == first && right == third
    -1
  elsif left == second && right == third
    -1
  elsif left == right
    0
  else
    1
  end

end