Fix bug when ean has zero as last digit (#9)

lib/br_documents/gtin/gtin.rb

@@ -22,7 +22,7 @@ def valid_checksum?
         (i + 1).even? ? (even += number.to_i) : (odd += number.to_i * 3)
       end
 
-      @code.chars.last.to_i == (10 - (odd + even) % 10)
+      @code.chars.last.to_i == ((10 - (odd + even)) % 10)
     end
   end
 end

lib/br_documents/version.rb

@@ -1,3 +1,3 @@
 module BrDocuments
-  VERSION = "0.1.0"
+  VERSION = "0.1.1"
 end

spec/gtin/gtin_spec.rb

@@ -27,6 +27,12 @@
         it { is_expected.to be_valid }
       end
 
+      context 'when the final digit is zero' do
+        subject { described_class.new('7898417964120') }
+
+        it { is_expected.to be_valid }
+      end
+
       context 'when the number of digits is different of 8, 13 or 14' do
         subject { described_class.new('12345678901234560') }