Make tag registry enumerable

lib/liquid/template.rb

@@ -19,6 +19,8 @@ module Liquid
     @@file_system = BlankFileSystem.new
 
     class TagRegistry
+      include Enumerable
+
       def initialize
         @tags = {}
         @cache = {}
@@ -41,6 +43,10 @@ module Liquid
         @cache.delete(tag_name)
       end
 
+      def each(&block)
+        @tags.each(&block)
+      end
+
       private
 
       def lookup_class(name)

test/unit/template_unit_test.rb

@@ -67,4 +67,10 @@ class TemplateUnitTest < Minitest::Test
     Template.tags.delete('fake')
     assert_nil Template.tags['fake']
   end
+
+  def test_tags_can_be_looped_over
+    Template.register_tag('fake', FakeTag)
+    result = Template.tags.map { |name, klass| [name, klass] }
+    assert result.include?(["fake", "TemplateUnitTest::FakeTag"])
+  end
 end