Fix Company.luhn_algorithm and add missing tests.

lib/faker/company.rb

@@ -178,7 +178,7 @@ def mod11(number)
  def luhn_algorithm(number)
  multiplications = []
 
- number.split(//).each_with_index do |digit, i|
+ number.reverse.split(//).each_with_index do |digit, i|
  multiplications << if i.even?
  digit.to_i * 2
  else

test/test_faker_company.rb

@@ -144,6 +144,21 @@ def test_south_african_trust_registration_number
  )
  end
 
+ def test_luhn_algorithm
+ # Odd length base for luhn algorithm
+ odd_base = Faker::Number.number([5, 7, 9, 11, 13].sample)
+ odd_luhn_complement = @tester.send(:luhn_algorithm, odd_base)
+ odd_control = "#{odd_base}#{odd_luhn_complement}"
+
+ # Even length base for luhn algorithm
+ even_base = Faker::Number.number([4, 6, 8, 10, 12].sample)
+ even_luhn_complement = @tester.send(:luhn_algorithm, even_base)
+ even_control = "#{even_base}#{even_luhn_complement}"
+
+ assert((luhn_checksum(odd_control) % 10).zero?)
+ assert((luhn_checksum(even_control) % 10).zero?)
+ end
+
  private
 
  def czech_o_n_checksum(org_no)
@@ -163,4 +178,13 @@ def abn_checksum(abn)
  (i.zero? ? n - 1 : n) * abn_weights[i]
  end.inject(:+)
  end
+
+ def luhn_checksum(luhn)
+ luhn_split = luhn.each_char.map(&:to_i).reverse.each_with_index.map do |n, i|
+ x = i.odd? ? n * 2 : n
+ x > 9 ? x - 9 : x
+ end
+
+ luhn_split.compact.inject(0) { |sum, x| sum + x }
+ end
 end