Merge pull request #27111 from maclover7/jm-xmlmini

Refactor ActiveSupport::XMLMini test suite

9 files changed, 317 insertions, 970 deletions

diff --git a/Gemfile b/Gemfile
index 10e146d887..37e5b4fd25 100644
--- a/Gemfile
+++ b/Gemfile
@@ -48,6 +48,7 @@ end
 # Active Support.
 gem "dalli", ">= 2.2.1"
 gem "listen", ">= 3.0.5", "< 3.2", require: false
+gem "libxml-ruby", platforms: :ruby
 
 # Active Job.
 group :job do
diff --git a/Gemfile.lock b/Gemfile.lock
index 06e822964b..bec01cda4a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -214,6 +214,7 @@ GEM
     kindlerb (1.0.1)
       mustache
       nokogiri
+    libxml-ruby (2.9.0)
     listen (3.1.5)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
@@ -381,6 +382,7 @@ DEPENDENCIES
   jquery-rails
   json (>= 2.0.0)
   kindlerb (>= 1.0.1)
+  libxml-ruby
   listen (>= 3.0.5, < 3.2)
   minitest (< 5.3.4)
   mocha (~> 0.14)
diff --git a/activesupport/test/xml_mini/jdom_engine_test.rb b/activesupport/test/xml_mini/jdom_engine_test.rb
index 816d57972c..a29949ab87 100644
--- a/activesupport/test/xml_mini/jdom_engine_test.rb
+++ b/activesupport/test/xml_mini/jdom_engine_test.rb
@@ -1,37 +1,9 @@
-if RUBY_PLATFORM.include?("java")
-  require "abstract_unit"
-  require "active_support/xml_mini"
-  require "active_support/core_ext/hash/conversions"
-
-  class JDOMEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
+require_relative "xml_mini_engine_test"
 
+XMLMiniEngineTest.run_with_platform("java") do
+  class JDOMEngineTest < XMLMiniEngineTest
     FILES_DIR = File.dirname(__FILE__) + "/../fixtures/xml"
 
-    def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "JDOM"
-    end
-
-    def teardown
-      XmlMini.backend = @default_backend
-    end
-
-    def test_file_from_xml
-      hash = Hash.from_xml(<<-eoxml)
-         <blog>
-           <logo type="file" name="logo.png" content_type="image/png">
-           </logo>
-         </blog>
-       eoxml
-      assert hash.has_key?("blog")
-      assert hash["blog"].has_key?("logo")
-
-      file = hash["blog"]["logo"]
-      assert_equal "logo.png", file.original_filename
-      assert_equal "image/png", file.content_type
-    end
-
     def test_not_allowed_to_expand_entities_to_files
       attack_xml = <<-EOT
       <!DOCTYPE member [
@@ -63,121 +35,18 @@ if RUBY_PLATFORM.include?("java")
       assert_equal "x", Hash.from_xml(attack_xml)["member"]
     end
 
-    def test_exception_thrown_on_expansion_attack
-      assert_raise Java::OrgXmlSax::SAXParseException do
-        attack_xml = <<-EOT
-      <!DOCTYPE member [
-        <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
-        <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
-        <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
-        <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
-        <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
-        <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
-        <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
-      ]>
-      <member>
-      &a;
-      </member>
-        EOT
-        Hash.from_xml(attack_xml)
-      end
-    end
-
-    def test_setting_JDOM_as_backend
-      XmlMini.backend = "JDOM"
-      assert_equal XmlMini_JDOM, XmlMini.backend
-    end
-
-    def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
-    end
-
-    def test_array_type_makes_an_array
-      assert_equal_rexml(<<-eoxml)
-      <blog>
-        <posts type="array">
-          <post>a post</post>
-          <post>another post</post>
-        </posts>
-      </blog>
-      eoxml
-    end
-
-    def test_one_node_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products/>
-      eoxml
-    end
-
-    def test_one_node_with_attributes_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products foo="bar"/>
-      eoxml
-    end
-
-    def test_products_node_with_book_node_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-    </products>
-      eoxml
-    end
-
-    def test_products_node_with_two_book_nodes_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-      <book name="america" id="67890" />
-    </products>
-      eoxml
-    end
-
-    def test_single_node_with_content_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products>
-        hello world
-      </products>
-      eoxml
-    end
-
-    def test_children_with_children
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        <book name="america" id="67890" />
-      </products>
-    </root>
-      eoxml
-    end
+    private
 
-    def test_children_with_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello everyone
-      </products>
-    </root>
-      eoxml
-    end
+      def engine
+        "JDOM"
+      end
 
-    def test_children_with_non_adjacent_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-      eoxml
-    end
+      def expansion_attack_error
+        Java::OrgXmlSax::SAXParseException
+      end
 
-    private
-      def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
-        assert_equal(hash, parsed_xml)
+      def extended_engine?
+        false
       end
   end
 end
diff --git a/activesupport/test/xml_mini/libxml_engine_test.rb b/activesupport/test/xml_mini/libxml_engine_test.rb
index 81b0d3c407..e3b06e24b7 100644
--- a/activesupport/test/xml_mini/libxml_engine_test.rb
+++ b/activesupport/test/xml_mini/libxml_engine_test.rb
@@ -1,203 +1,20 @@
-begin
-  require "libxml"
-rescue LoadError
-  # Skip libxml tests
-else
-  require "abstract_unit"
-  require "active_support/xml_mini"
-  require "active_support/core_ext/hash/conversions"
-
-  class LibxmlEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
+require_relative "xml_mini_engine_test"
 
+XMLMiniEngineTest.run_with_gem("libxml") do
+  class LibxmlEngineTest < XMLMiniEngineTest
     def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "LibXML"
-
+      super
       LibXML::XML::Error.set_handler(&lambda { |error| }) #silence libxml, exceptions will do
     end
 
-    def teardown
-      XmlMini.backend = @default_backend
-    end
+    private
 
-    def test_exception_thrown_on_expansion_attack
-      assert_raise LibXML::XML::Error do
-        attack_xml = %{<?xml version="1.0" encoding="UTF-8"?>
-        <!DOCTYPE member [
-          <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
-          <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
-          <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
-          <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
-          <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
-          <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
-          <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
-        ]>
-        <member>
-        &a;
-        </member>
-       }
-        Hash.from_xml(attack_xml)
+      def engine
+        "LibXML"
       end
-    end
-
-    def test_setting_libxml_as_backend
-      XmlMini.backend = "LibXML"
-      assert_equal XmlMini_LibXML, XmlMini.backend
-    end
-
-    def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
-    end
-
-    def test_array_type_makes_an_array
-      assert_equal_rexml(<<-eoxml)
-      <blog>
-        <posts type="array">
-          <post>a post</post>
-          <post>another post</post>
-        </posts>
-      </blog>
-    eoxml
-    end
-
-    def test_one_node_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products/>
-      eoxml
-    end
-
-    def test_one_node_with_attributes_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products foo="bar"/>
-      eoxml
-    end
-
-    def test_products_node_with_book_node_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-    </products>
-    eoxml
-    end
-
-    def test_products_node_with_two_book_nodes_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-      <book name="america" id="67890" />
-    </products>
-    eoxml
-    end
-
-    def test_single_node_with_content_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products>
-        hello world
-      </products>
-    eoxml
-    end
 
-    def test_children_with_children
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        <book name="america" id="67890" />
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello everyone
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_non_adjacent_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-    end
-
-    def test_parse_from_io
-      io = StringIO.new(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-      assert_equal_rexml(io)
-    end
-
-    def test_children_with_simple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_multiple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text_and_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello <![CDATA[cdatablock]]>
-        morning
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>   </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text_and_attribute
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products type="file">   </products>
-    </root>
-    eoxml
-    end
-
-    private
-      def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
-        xml.rewind if xml.respond_to?(:rewind)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
-        assert_equal(hash, parsed_xml)
+      def expansion_attack_error
+        LibXML::XML::Error
       end
   end
-
 end
diff --git a/activesupport/test/xml_mini/libxmlsax_engine_test.rb b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
index e25fa2813c..b677f115e5 100644
--- a/activesupport/test/xml_mini/libxmlsax_engine_test.rb
+++ b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
@@ -1,195 +1,15 @@
-begin
-  require "libxml"
-rescue LoadError
-  # Skip libxml tests
-else
-  require "abstract_unit"
-  require "active_support/xml_mini"
-  require "active_support/core_ext/hash/conversions"
+require_relative "xml_mini_engine_test"
 
-  class LibXMLSAXEngineTest < ActiveSupport::TestCase
-    include ActiveSupport
-
-    def setup
-      @default_backend = XmlMini.backend
-      XmlMini.backend = "LibXMLSAX"
-    end
-
-    def teardown
-      XmlMini.backend = @default_backend
-    end
-
-    def test_exception_thrown_on_expansion_attack
-      assert_raise LibXML::XML::Error do
-        attack_xml = <<-EOT
-      <?xml version="1.0" encoding="UTF-8"?>
-      <!DOCTYPE member [
-        <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
-        <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
-        <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
-        <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
-        <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
-        <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
-        <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
-      ]>
-      <member>
-      &a;
-      </member>
-      EOT
+XMLMiniEngineTest.run_with_gem("libxml") do
+  class LibXMLSAXEngineTest < XMLMiniEngineTest
+    private
 
-        Hash.from_xml(attack_xml)
+      def engine
+        "LibXMLSAX"
       end
-    end
-
-    def test_setting_libxml_as_backend
-      XmlMini.backend = "LibXMLSAX"
-      assert_equal XmlMini_LibXMLSAX, XmlMini.backend
-    end
-
-    def test_blank_returns_empty_hash
-      assert_equal({}, XmlMini.parse(nil))
-      assert_equal({}, XmlMini.parse(""))
-    end
-
-    def test_array_type_makes_an_array
-      assert_equal_rexml(<<-eoxml)
-      <blog>
-        <posts type="array">
-          <post>a post</post>
-          <post>another post</post>
-        </posts>
-      </blog>
-    eoxml
-    end
-
-    def test_one_node_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products/>
-      eoxml
-    end
-
-    def test_one_node_with_attributes_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products foo="bar"/>
-      eoxml
-    end
-
-    def test_products_node_with_book_node_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-    </products>
-    eoxml
-    end
-
-    def test_products_node_with_two_book_nodes_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-      <book name="america" id="67890" />
-    </products>
-    eoxml
-    end
 
-    def test_single_node_with_content_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products>
-        hello world
-      </products>
-    eoxml
-    end
-
-    def test_children_with_children
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        <book name="america" id="67890" />
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello everyone
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_non_adjacent_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-    end
-
-    def test_parse_from_io
-      io = StringIO.new(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-      assert_equal_rexml(io)
-    end
-
-    def test_children_with_simple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_multiple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text_and_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello <![CDATA[cdatablock]]>
-        morning
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>   </products>
-    </root>
-    eoxml
-    end
-
-    private
-      def assert_equal_rexml(xml)
-        parsed_xml = XmlMini.parse(xml)
-        xml.rewind if xml.respond_to?(:rewind)
-        hash = XmlMini.with_backend("REXML") { XmlMini.parse(xml) }
-        assert_equal(hash, parsed_xml)
+      def expansion_attack_error
+        LibXML::XML::Error
       end
   end
-
 end
diff --git a/activesupport/test/xml_mini/nokogiri_engine_test.rb b/activesupport/test/xml_mini/nokogiri_engine_test.rb
index 44b82da4e4..e90dfa173f 100644
--- a/activesupport/test/xml_mini/nokogiri_engine_test.rb
+++ b/activesupport/test/xml_mini/nokogiri_engine_test.rb
@@ -1,215 +1,15 @@
-begin
-  require "nokogiri"
-rescue LoadError
-  # Skip nokogiri tests
-else
-  require "abstract_unit"
-  require "active_support/xml_mini"
-  require "active_support/core_ext/hash/conversions"
+require_relative "xml_mini_engine_test"
 
-  class NokogiriEngineTest < ActiveSupport::TestCase
-    def setup
-      @default_backend = ActiveSupport::XmlMini.backend
-      ActiveSupport::XmlMini.backend = "Nokogiri"
-    end
-
-    def teardown
-      ActiveSupport::XmlMini.backend = @default_backend
-    end
-
-    def test_file_from_xml
-      hash = Hash.from_xml(<<-eoxml)
-      <blog>
-        <logo type="file" name="logo.png" content_type="image/png">
-        </logo>
-      </blog>
-    eoxml
-      assert hash.has_key?("blog")
-      assert hash["blog"].has_key?("logo")
-
-      file = hash["blog"]["logo"]
-      assert_equal "logo.png", file.original_filename
-      assert_equal "image/png", file.content_type
-    end
+XMLMiniEngineTest.run_with_gem("nokogiri") do
+  class NokogiriEngineTest < XMLMiniEngineTest
+    private
 
-    def test_exception_thrown_on_expansion_attack
-      assert_raise Nokogiri::XML::SyntaxError do
-        attack_xml = <<-EOT
-      <?xml version="1.0" encoding="UTF-8"?>
-      <!DOCTYPE member [
-        <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
-        <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
-        <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
-        <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
-        <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
-        <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
-        <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
-      ]>
-      <member>
-      &a;
-      </member>
-      EOT
-        Hash.from_xml(attack_xml)
+      def engine
+        "Nokogiri"
       end
-    end
-
-    def test_setting_nokogiri_as_backend
-      ActiveSupport::XmlMini.backend = "Nokogiri"
-      assert_equal ActiveSupport::XmlMini_Nokogiri, ActiveSupport::XmlMini.backend
-    end
-
-    def test_blank_returns_empty_hash
-      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
-      assert_equal({}, ActiveSupport::XmlMini.parse(""))
-    end
-
-    def test_array_type_makes_an_array
-      assert_equal_rexml(<<-eoxml)
-      <blog>
-        <posts type="array">
-          <post>a post</post>
-          <post>another post</post>
-        </posts>
-      </blog>
-    eoxml
-    end
-
-    def test_one_node_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products/>
-      eoxml
-    end
-
-    def test_one_node_with_attributes_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products foo="bar"/>
-      eoxml
-    end
-
-    def test_products_node_with_book_node_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-    </products>
-    eoxml
-    end
-
-    def test_products_node_with_two_book_nodes_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-      <book name="america" id="67890" />
-    </products>
-    eoxml
-    end
-
-    def test_single_node_with_content_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products>
-        hello world
-      </products>
-    eoxml
-    end
 
-    def test_children_with_children
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        <book name="america" id="67890" />
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello everyone
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_non_adjacent_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-    end
-
-    def test_parse_from_io
-      io = StringIO.new(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-      assert_equal_rexml(io)
-    end
-
-    def test_children_with_simple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_multiple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text_and_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello <![CDATA[cdatablock]]>
-        morning
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>   </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text_and_attribute
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products type="file">   </products>
-    </root>
-    eoxml
-    end
-
-    private
-      def assert_equal_rexml(xml)
-        parsed_xml = ActiveSupport::XmlMini.parse(xml)
-        xml.rewind if xml.respond_to?(:rewind)
-        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
-        assert_equal(hash, parsed_xml)
+      def expansion_attack_error
+        Nokogiri::XML::SyntaxError
       end
   end
-
 end
diff --git a/activesupport/test/xml_mini/nokogirisax_engine_test.rb b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
index 24b35cadf6..0f559dc7a5 100644
--- a/activesupport/test/xml_mini/nokogirisax_engine_test.rb
+++ b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
@@ -1,216 +1,15 @@
-begin
-  require "nokogiri"
-rescue LoadError
-  # Skip nokogiri tests
-else
-  require "abstract_unit"
-  require "active_support/xml_mini"
-  require "active_support/core_ext/hash/conversions"
+require_relative "xml_mini_engine_test"
 
-  class NokogiriSAXEngineTest < ActiveSupport::TestCase
-    def setup
-      @default_backend = ActiveSupport::XmlMini.backend
-      ActiveSupport::XmlMini.backend = "NokogiriSAX"
-    end
-
-    def teardown
-      ActiveSupport::XmlMini.backend = @default_backend
-    end
-
-    def test_file_from_xml
-      hash = Hash.from_xml(<<-eoxml)
-      <blog>
-        <logo type="file" name="logo.png" content_type="image/png">
-        </logo>
-      </blog>
-    eoxml
-      assert hash.has_key?("blog")
-      assert hash["blog"].has_key?("logo")
-
-      file = hash["blog"]["logo"]
-      assert_equal "logo.png", file.original_filename
-      assert_equal "image/png", file.content_type
-    end
-
-    def test_exception_thrown_on_expansion_attack
-      assert_raise RuntimeError do
-        attack_xml = <<-EOT
-      <?xml version="1.0" encoding="UTF-8"?>
-      <!DOCTYPE member [
-        <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
-        <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
-        <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
-        <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
-        <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
-        <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
-        <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
-      ]>
-      <member>
-      &a;
-      </member>
-      EOT
+XMLMiniEngineTest.run_with_gem("nokogiri") do
+  class NokogiriSAXEngineTest < XMLMiniEngineTest
+    private
 
-        Hash.from_xml(attack_xml)
+      def engine
+        "NokogiriSAX"
       end
-    end
-
-    def test_setting_nokogirisax_as_backend
-      ActiveSupport::XmlMini.backend = "NokogiriSAX"
-      assert_equal ActiveSupport::XmlMini_NokogiriSAX, ActiveSupport::XmlMini.backend
-    end
-
-    def test_blank_returns_empty_hash
-      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
-      assert_equal({}, ActiveSupport::XmlMini.parse(""))
-    end
-
-    def test_array_type_makes_an_array
-      assert_equal_rexml(<<-eoxml)
-      <blog>
-        <posts type="array">
-          <post>a post</post>
-          <post>another post</post>
-        </posts>
-      </blog>
-    eoxml
-    end
-
-    def test_one_node_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products/>
-      eoxml
-    end
-
-    def test_one_node_with_attributes_document_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products foo="bar"/>
-      eoxml
-    end
-
-    def test_products_node_with_book_node_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-    </products>
-    eoxml
-    end
-
-    def test_products_node_with_two_book_nodes_as_hash
-      assert_equal_rexml(<<-eoxml)
-    <products>
-      <book name="awesome" id="12345" />
-      <book name="america" id="67890" />
-    </products>
-    eoxml
-    end
 
-    def test_single_node_with_content_as_hash
-      assert_equal_rexml(<<-eoxml)
-      <products>
-        hello world
-      </products>
-    eoxml
-    end
-
-    def test_children_with_children
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        <book name="america" id="67890" />
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello everyone
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_non_adjacent_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-    end
-
-    def test_parse_from_io
-      io = StringIO.new(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-      assert_equal_rexml(io)
-    end
-
-    def test_children_with_simple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_multiple_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-         <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_text_and_cdata
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>
-        hello <![CDATA[cdatablock]]>
-        morning
-      </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products>   </products>
-    </root>
-    eoxml
-    end
-
-    def test_children_with_blank_text_and_attribute
-      assert_equal_rexml(<<-eoxml)
-    <root>
-      <products type="file">   </products>
-    </root>
-    eoxml
-    end
-
-    private
-      def assert_equal_rexml(xml)
-        parsed_xml = ActiveSupport::XmlMini.parse(xml)
-        xml.rewind if xml.respond_to?(:rewind)
-        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
-        assert_equal(hash, parsed_xml)
+      def expansion_attack_error
+        RuntimeError
       end
   end
-
 end
diff --git a/activesupport/test/xml_mini/rexml_engine_test.rb b/activesupport/test/xml_mini/rexml_engine_test.rb
index dc62f3f671..085cf2caf7 100644
--- a/activesupport/test/xml_mini/rexml_engine_test.rb
+++ b/activesupport/test/xml_mini/rexml_engine_test.rb
@@ -1,44 +1,26 @@
-require "abstract_unit"
-require "active_support/xml_mini"
+require_relative "xml_mini_engine_test"
 
-class REXMLEngineTest < ActiveSupport::TestCase
+class REXMLEngineTest < XMLMiniEngineTest
   def test_default_is_rexml
     assert_equal ActiveSupport::XmlMini_REXML, ActiveSupport::XmlMini.backend
   end
 
-  def test_set_rexml_as_backend
-    ActiveSupport::XmlMini.backend = "REXML"
-    assert_equal ActiveSupport::XmlMini_REXML, ActiveSupport::XmlMini.backend
-  end
-
-  def test_parse_from_io
-    ActiveSupport::XmlMini.backend = "REXML"
-    io = StringIO.new(<<-eoxml)
-    <root>
-      good
-      <products>
-        hello everyone
-      </products>
-      morning
-    </root>
-    eoxml
-    hash = ActiveSupport::XmlMini.parse(io)
-    assert hash.has_key?("root")
-    assert hash["root"].has_key?("products")
-    assert_match "good", hash["root"]["__content__"]
-    products = hash["root"]["products"]
-    assert products.has_key?("__content__")
-    assert_match "hello everyone", products["__content__"]
-  end
-
   def test_parse_from_empty_string
-    ActiveSupport::XmlMini.backend = "REXML"
     assert_equal({}, ActiveSupport::XmlMini.parse(""))
   end
 
   def test_parse_from_frozen_string
-    ActiveSupport::XmlMini.backend = "REXML"
     xml_string = "<root></root>".freeze
     assert_equal({ "root" => {} }, ActiveSupport::XmlMini.parse(xml_string))
   end
+
+  private
+
+    def engine
+      "REXML"
+    end
+
+    def expansion_attack_error
+      RuntimeError
+    end
 end
diff --git a/activesupport/test/xml_mini/xml_mini_engine_test.rb b/activesupport/test/xml_mini/xml_mini_engine_test.rb
new file mode 100644
index 0000000000..5be9084c9d
--- /dev/null
+++ b/activesupport/test/xml_mini/xml_mini_engine_test.rb
@@ -0,0 +1,257 @@
+require "abstract_unit"
+require "active_support/xml_mini"
+require "active_support/core_ext/hash/conversions"
+
+class XMLMiniEngineTest < ActiveSupport::TestCase
+  def self.run_with_gem(gem_name)
+    require gem_name
+    yield
+  rescue LoadError
+    # Skip tests unless gem is available
+  end
+
+  def self.run_with_platform(platform_name)
+    yield if RUBY_PLATFORM.include?(platform_name)
+  end
+
+  def self.inherited(base)
+    base.include EngineTests
+    super
+  end
+
+  def setup
+    @default_backend = ActiveSupport::XmlMini.backend
+    ActiveSupport::XmlMini.backend = engine
+    super
+  end
+
+  def teardown
+    ActiveSupport::XmlMini.backend = @default_backend
+    super
+  end
+
+  module EngineTests
+    def test_file_from_xml
+      hash = Hash.from_xml(<<-eoxml)
+        <blog>
+          <logo type="file" name="logo.png" content_type="image/png">
+          </logo>
+        </blog>
+      eoxml
+      assert hash.key?("blog")
+      assert hash["blog"].key?("logo")
+
+      file = hash["blog"]["logo"]
+      assert_equal "logo.png", file.original_filename
+      assert_equal "image/png", file.content_type
+    end
+
+    def test_exception_thrown_on_expansion_attack
+      assert_raise expansion_attack_error do
+        Hash.from_xml(<<-eoxml)
+          <?xml version="1.0" encoding="UTF-8"?>
+          <!DOCTYPE member [
+            <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
+            <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
+            <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
+            <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
+            <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
+            <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
+            <!ENTITY g "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx">
+          ]>
+          <member>
+            &a;
+          </member>
+      eoxml
+      end
+    end
+
+    def test_setting_backend
+      assert_engine_class ActiveSupport::XmlMini.backend
+    end
+
+    def test_blank_returns_empty_hash
+      assert_equal({}, ActiveSupport::XmlMini.parse(nil))
+      assert_equal({}, ActiveSupport::XmlMini.parse(""))
+    end
+
+    def test_array_type_makes_an_array
+      assert_equal_rexml(<<-eoxml)
+        <blog>
+          <posts type="array">
+            <post>a post</post>
+            <post>another post</post>
+          </posts>
+        </blog>
+      eoxml
+    end
+
+    def test_one_node_document_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products/>
+      eoxml
+    end
+
+    def test_one_node_with_attributes_document_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products foo="bar"/>
+      eoxml
+    end
+
+    def test_products_node_with_book_node_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          <book name="awesome" id="12345" />
+        </products>
+      eoxml
+    end
+
+    def test_products_node_with_two_book_nodes_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          <book name="awesome" id="12345" />
+          <book name="america" id="67890" />
+        </products>
+      eoxml
+    end
+
+    def test_single_node_with_content_as_hash
+      assert_equal_rexml(<<-eoxml)
+        <products>
+          hello world
+        </products>
+      eoxml
+    end
+
+    def test_children_with_children
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            <book name="america" id="67890" />
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_text
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            hello everyone
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_non_adjacent_text
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          good
+          <products>
+            hello everyone
+          </products>
+          morning
+        </root>
+      eoxml
+    end
+
+    def test_parse_from_io
+      skip_unless_extended_engine
+
+      assert_equal_rexml(StringIO.new(<<-eoxml))
+        <root>
+          good
+          <products>
+            hello everyone
+          </products>
+          morning
+        </root>
+      eoxml
+    end
+
+    def test_children_with_simple_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+             <![CDATA[cdatablock]]>
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_multiple_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+             <![CDATA[cdatablock1]]><![CDATA[cdatablock2]]>
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_text_and_cdata
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>
+            hello <![CDATA[cdatablock]]>
+            morning
+          </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_blank_text
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products>   </products>
+        </root>
+      eoxml
+    end
+
+    def test_children_with_blank_text_and_attribute
+      skip_unless_extended_engine
+
+      assert_equal_rexml(<<-eoxml)
+        <root>
+          <products type="file">   </products>
+        </root>
+      eoxml
+    end
+
+    private
+      def engine
+        raise NotImplementedError
+      end
+
+      def assert_engine_class(actual)
+        assert_equal ActiveSupport.const_get("XmlMini_#{engine}"), actual
+      end
+
+      def assert_equal_rexml(xml)
+        parsed_xml = ActiveSupport::XmlMini.parse(xml)
+        xml.rewind if xml.respond_to?(:rewind)
+        hash = ActiveSupport::XmlMini.with_backend("REXML") { ActiveSupport::XmlMini.parse(xml) }
+        assert_equal(hash, parsed_xml)
+      end
+
+      def expansion_attack_error
+        raise NotImplementedError
+      end
+
+      def extended_engine?
+        true
+      end
+
+      def skip_unless_extended_engine
+        skip "#{engine} is not an extended engine" unless extended_engine?
+      end
+  end
+end