Removed unf dependency for ruby > 2.2

domain_name.gemspec

@@ -28,7 +28,7 @@ Suffix List.
     "README.md"
   ]
 
-  gem.add_runtime_dependency("unf", ["< 1.0.0", ">= 0.0.5"])
+  gem.add_runtime_dependency("unf", ["< 1.0.0", ">= 0.0.5"]) if RUBY_VERSION < "2.2"
   gem.add_development_dependency("test-unit", "~> 2.5.5")
   gem.add_development_dependency("bundler", [">= 1.2.0"])
   gem.add_development_dependency("rake", [">= 0.9.2.2", *("< 11" if RUBY_VERSION < "1.9")])

lib/domain_name.rb

@@ -8,8 +8,12 @@
 require 'domain_name/version'
 require 'domain_name/punycode'
 require 'domain_name/etld_data'
-require 'unf'
 require 'ipaddr'
+if RUBY_VERSION < '2.2'
+  require 'unf'
+else
+  require 'unicode_normalize/normalize'
+end
 
 # Represents a domain name ready for extracting its registered domain
 # and TLD.
@@ -285,8 +289,14 @@ def inspect
   class << self
     # Normalizes a _domain_ using the Punycode algorithm as necessary.
     # The result will be a downcased, ASCII-only string.
-    def normalize(domain)
-      DomainName::Punycode.encode_hostname(domain.chomp(DOT).to_nfc).downcase
+    if RUBY_VERSION >= '2.2'
+      def normalize(domain)
+        DomainName::Punycode.encode_hostname(domain.chomp(DOT).unicode_normalize).downcase
+      end
+    else
+      def normalize(domain)
+        DomainName::Punycode.encode_hostname(domain.chomp(DOT).to_nfc).downcase
+      end
     end
   end
 end

test/test_domain_name-punycode.rb

@@ -91,7 +91,12 @@ class TestDomainName < Test::Unit::TestCase
         '-> $1.00 <--']
     ].each { |title, cps, punycode|
       assert_equal punycode, DomainName::Punycode.encode(cps.pack('U*')), title
-      assert_equal cps.pack('U*').to_nfc, DomainName::Punycode.decode(punycode), title
+      cps_norm = if RUBY_VERSION >= '2.2'
+          cps.pack('U*').unicode_normalize
+        else
+          cps.pack('U*').to_nfc
+        end
+      assert_equal cps_norm, DomainName::Punycode.decode(punycode), title
     }
   end
 end