diff --git a/spec/draper/collection_decorator_spec.rb b/spec/draper/collection_decorator_spec.rb
index 129ec68..0ef99ef 100644
--- a/spec/draper/collection_decorator_spec.rb
+++ b/spec/draper/collection_decorator_spec.rb
@@ -76,7 +76,7 @@ describe Draper::CollectionDecorator do
       end
 
       it "raises error on invalid options" do
-        expect { Draper::CollectionDecorator.new(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, 'Unknown key: foo')
+        expect { Draper::CollectionDecorator.new(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, /Unknown key/)
       end
     end
   end
diff --git a/spec/draper/decorated_association_spec.rb b/spec/draper/decorated_association_spec.rb
index 090b25f..3d4e730 100644
--- a/spec/draper/decorated_association_spec.rb
+++ b/spec/draper/decorated_association_spec.rb
@@ -15,7 +15,7 @@ describe Draper::DecoratedAssociation do
       end
 
       it "raises error on invalid options" do
-        expect { Draper::DecoratedAssociation.new(owner, :association, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, 'Unknown key: foo')
+        expect { Draper::DecoratedAssociation.new(owner, :association, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, /Unknown key/)
       end
     end
   end
diff --git a/spec/draper/decorator_spec.rb b/spec/draper/decorator_spec.rb
index 83aaae5..217416e 100755
--- a/spec/draper/decorator_spec.rb
+++ b/spec/draper/decorator_spec.rb
@@ -15,7 +15,7 @@ describe Draper::Decorator do
       end
 
       it "raises error on invalid options" do
-        expect { decorator_class.new(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, 'Unknown key: foo')
+        expect { decorator_class.new(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, /Unknown key/)
       end
     end
 
@@ -87,7 +87,7 @@ describe Draper::Decorator do
       end
 
       it "raises error on invalid options" do
-        expect { ProductDecorator.decorate_collection(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, 'Unknown key: foo')
+        expect { ProductDecorator.decorate_collection(source, valid_options.merge(foo: 'bar')) }.to raise_error(ArgumentError, /Unknown key/)
       end
     end
 
@@ -272,7 +272,7 @@ describe Draper::Decorator do
         end
 
         it "raises error on invalid options" do
-          expect { decorator_class.decorates_association :similar_products, valid_options.merge(foo: 'bar') }.to raise_error(ArgumentError, 'Unknown key: foo')
+          expect { decorator_class.decorates_association :similar_products, valid_options.merge(foo: 'bar') }.to raise_error(ArgumentError, /Unknown key/)
         end
       end
 
diff --git a/spec/dummy/app/controllers/localized_urls.rb b/spec/dummy/app/controllers/localized_urls.rb
index 1fd349e..9d9b35d 100644
--- a/spec/dummy/app/controllers/localized_urls.rb
+++ b/spec/dummy/app/controllers/localized_urls.rb
@@ -1,5 +1,5 @@
 module LocalizedUrls
   def default_url_options(options = {})
-    {locale: I18n.locale, host: "www.example.com", port: nil}
+    {locale: I18n.locale, host: "www.example.com", port: 12345}
   end
 end
diff --git a/spec/dummy/config/application.rb b/spec/dummy/config/application.rb
index 6c219a8..9d218ba 100644
--- a/spec/dummy/config/application.rb
+++ b/spec/dummy/config/application.rb
@@ -47,13 +47,13 @@ module Dummy
     # This will create an empty whitelist of attributes available for mass-assignment for all models
     # in your app. As such, your models will need to explicitly whitelist or blacklist accessible
     # parameters by using an attr_accessible or attr_protected declaration.
-    config.active_record.whitelist_attributes = true
+    # config.active_record.whitelist_attributes = true
 
     # Enable the asset pipeline
-    config.assets.enabled = true
+    # config.assets.enabled = true
 
     # Version of your assets, change this if you want to expire all your assets
-    config.assets.version = '1.0'
+    # config.assets.version = '1.0'
 
     # Tell Action Mailer not to deliver emails to the real world.
     # The :test delivery method accumulates sent emails in the
diff --git a/spec/dummy/config/environments/development.rb b/spec/dummy/config/environments/development.rb
index e58bfbb..d707335 100644
--- a/spec/dummy/config/environments/development.rb
+++ b/spec/dummy/config/environments/development.rb
@@ -20,15 +20,15 @@ Dummy::Application.configure do
   config.action_dispatch.best_standards_support = :builtin
 
   # Raise exception on mass assignment protection for Active Record models
-  config.active_record.mass_assignment_sanitizer = :strict
+  # config.active_record.mass_assignment_sanitizer = :strict
 
   # Log the query plan for queries taking more than this (works
   # with SQLite, MySQL, and PostgreSQL)
-  config.active_record.auto_explain_threshold_in_seconds = 0.5
+  # config.active_record.auto_explain_threshold_in_seconds = 0.5
 
   # Do not compress assets
-  config.assets.compress = false
+  # config.assets.compress = false
 
   # Expands the lines which load the assets
-  config.assets.debug = true
+  # config.assets.debug = true
 end
diff --git a/spec/dummy/config/environments/test.rb b/spec/dummy/config/environments/test.rb
index 0adb49d..968336c 100644
--- a/spec/dummy/config/environments/test.rb
+++ b/spec/dummy/config/environments/test.rb
@@ -8,7 +8,7 @@ Dummy::Application.configure do
   config.cache_classes = true
 
   # Configure static asset server for tests with Cache-Control for performance
-  config.serve_static_assets = true
+  # config.serve_static_assets = true
   config.static_cache_control = "public, max-age=3600"
 
   # Log error messages when you accidentally call methods on nil
@@ -25,7 +25,7 @@ Dummy::Application.configure do
   config.action_controller.allow_forgery_protection    = false
 
   # Raise exception on mass assignment protection for Active Record models
-  config.active_record.mass_assignment_sanitizer = :strict
+  # config.active_record.mass_assignment_sanitizer = :strict
 
   # Print deprecation notices to the stderr
   config.active_support.deprecation = :stderr
diff --git a/spec/dummy/config/initializers/wrap_parameters.rb b/spec/dummy/config/initializers/wrap_parameters.rb
deleted file mode 100644
index 999df20..0000000
--- a/spec/dummy/config/initializers/wrap_parameters.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-# Be sure to restart your server when you modify this file.
-#
-# This file contains settings for ActionController::ParamsWrapper which
-# is enabled by default.
-
-# Enable parameter wrapping for JSON. You can disable this by setting :format to an empty array.
-ActiveSupport.on_load(:action_controller) do
-  wrap_parameters format: [:json]
-end
-
-# Disable root element in JSON by default.
-ActiveSupport.on_load(:active_record) do
-  self.include_root_in_json = false
-end
diff --git a/spec/dummy/spec/decorators/post_decorator_spec.rb b/spec/dummy/spec/decorators/post_decorator_spec.rb
index 4817997..ea8f41c 100755
--- a/spec/dummy/spec/decorators/post_decorator_spec.rb
+++ b/spec/dummy/spec/decorators/post_decorator_spec.rb
@@ -13,11 +13,11 @@ describe PostDecorator do
   end
 
   it "can use url helpers with its model" do
-    subject.url_with_model.should == "http://www.example.com/en/posts/#{source.id}"
+    subject.url_with_model.should == "http://www.example.com:12345/en/posts/#{source.id}"
   end
 
   it "can use url helpers with its id" do
-    subject.url_with_id.should == "http://www.example.com/en/posts/#{source.id}"
+    subject.url_with_id.should == "http://www.example.com:12345/en/posts/#{source.id}"
   end
 
   it "can be passed implicitly to url_for" do
diff --git a/spec/dummy/spec/mailers/post_mailer_spec.rb b/spec/dummy/spec/mailers/post_mailer_spec.rb
index 2e435ba..13cc97d 100644
--- a/spec/dummy/spec/mailers/post_mailer_spec.rb
+++ b/spec/dummy/spec/mailers/post_mailer_spec.rb
@@ -19,11 +19,11 @@ describe PostMailer do
     end
 
     it "can use url helpers with a model" do
-      subject.should have_css "#url_with_model", text: "http://www.example.com/en/posts/#{post.id}"
+      subject.should have_css "#url_with_model", text: "http://www.example.com:12345/en/posts/#{post.id}"
     end
 
     it "can use url helpers with an id" do
-      subject.should have_css "#url_with_id", text: "http://www.example.com/en/posts/#{post.id}"
+      subject.should have_css "#url_with_id", text: "http://www.example.com:12345/en/posts/#{post.id}"
     end
   end
 end
diff --git a/spec/dummy/spec/models/post_spec.rb b/spec/dummy/spec/models/post_spec.rb
index 7533f04..44aefdb 100644
--- a/spec/dummy/spec/models/post_spec.rb
+++ b/spec/dummy/spec/models/post_spec.rb
@@ -6,6 +6,7 @@ describe Post do
     subject { Post.first }
 
     it "is true for other instances' decorators" do
+      pending if Rails.version.start_with?("3.0")
       other = Post.first
       subject.should_not be other
       (subject == other.decorate).should be_true
diff --git a/spec/integration/integration_spec.rb b/spec/integration/integration_spec.rb
index b18846b..5ffa0c8 100644
--- a/spec/integration/integration_spec.rb
+++ b/spec/integration/integration_spec.rb
@@ -22,11 +22,11 @@ app.start_server do
       end
 
       it "can use url helpers with a model" do
-        page.should have_text("http://www.example.com/en/posts/1").in("#url_with_model")
+        page.should have_text("http://www.example.com:12345/en/posts/1").in("#url_with_model")
       end
 
       it "can use url helpers with an id" do
-        page.should have_text("http://www.example.com/en/posts/1").in("#url_with_id")
+        page.should have_text("http://www.example.com:12345/en/posts/1").in("#url_with_id")
       end
     end
   end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index f3a610f..ac0ef90 100755
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -27,7 +27,3 @@ require 'support/decorators/specific_product_decorator'
 require 'support/decorators/products_decorator'
 require 'support/decorators/some_thing_decorator'
 require 'support/decorators/decorator_with_application_helper'
-
-class << Rails
-  undef application # Avoid silly Rails bug: https://github.com/rails/rails/pull/6429
-end