diff --git a/Appraisals b/Appraisals
index 8e976665..8d1e20c9 100644
--- a/Appraisals
+++ b/Appraisals
@@ -26,6 +26,7 @@ appraise '4.0' do
   gem 'bcrypt-ruby', '~> 3.0.0' #FIXME: This should be ~> 3.1.0 for Rails 4.0
   gem 'jquery-rails'
   gem 'sass-rails', '~> 4.0.0'
+  gem 'activeresource', require: 'active_resource'
 
   # Test suite makes heavy use of attr_accessible
   gem 'protected_attributes'
diff --git a/NEWS.md b/NEWS.md
index 8bb280e6..04bd87da 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # HEAD
 
+* Fix a regression with context-dependent validations in ActiveResource
+
 * shoulda-matchers is now fully compatible with Rails 4.
 
 * When not using RSpec, shoulda-matchers is now auto-included into
diff --git a/gemfiles/4.0.gemfile b/gemfiles/4.0.gemfile
index 9fefc4a9..b8f55bf2 100644
--- a/gemfiles/4.0.gemfile
+++ b/gemfiles/4.0.gemfile
@@ -13,6 +13,7 @@ gem "rails", "4.0.0"
 gem "bcrypt-ruby", "~> 3.0.0"
 gem "jquery-rails"
 gem "sass-rails", "~> 4.0.0"
+gem "activeresource", :require=>"active_resource"
 gem "protected_attributes"
 
 gemspec :path=>"../"
\ No newline at end of file
diff --git a/gemfiles/4.0.gemfile.lock b/gemfiles/4.0.gemfile.lock
index 7219b102..b33c09fb 100644
--- a/gemfiles/4.0.gemfile.lock
+++ b/gemfiles/4.0.gemfile.lock
@@ -25,6 +25,10 @@ GEM
       activesupport (= 4.0.0)
       arel (~> 4.0.0)
     activerecord-deprecated_finders (1.0.3)
+    activeresource (4.0.0)
+      activemodel (~> 4.0)
+      activesupport (~> 4.0)
+      rails-observers (~> 0.1.1)
     activesupport (4.0.0)
       i18n (~> 0.6, >= 0.6.4)
       minitest (~> 4.2)
@@ -86,6 +90,8 @@ GEM
       bundler (>= 1.3.0, < 2.0)
       railties (= 4.0.0)
       sprockets-rails (~> 2.0.0)
+    rails-observers (0.1.2)
+      activemodel (~> 4.0)
     railties (4.0.0)
       actionpack (= 4.0.0)
       activesupport (= 4.0.0)
@@ -134,6 +140,7 @@ PLATFORMS
 DEPENDENCIES
   activerecord-jdbc-adapter
   activerecord-jdbcsqlite3-adapter
+  activeresource
   appraisal (~> 0.4)
   aruba
   bcrypt-ruby (~> 3.0.0)
diff --git a/lib/shoulda/matchers/active_model/validation_message_finder.rb b/lib/shoulda/matchers/active_model/validation_message_finder.rb
index 7b96ef5d..d36d9754 100644
--- a/lib/shoulda/matchers/active_model/validation_message_finder.rb
+++ b/lib/shoulda/matchers/active_model/validation_message_finder.rb
@@ -59,7 +59,7 @@ module Shoulda
         end
 
         def validate_instance
-          @instance.valid?(@context)
+          @instance.valid?(*@context)
           @instance
         end
       end
diff --git a/spec/shoulda/matchers/active_model/validate_presence_of_matcher_spec.rb b/spec/shoulda/matchers/active_model/validate_presence_of_matcher_spec.rb
index d544d8b2..209cfe60 100644
--- a/spec/shoulda/matchers/active_model/validate_presence_of_matcher_spec.rb
+++ b/spec/shoulda/matchers/active_model/validate_presence_of_matcher_spec.rb
@@ -134,6 +134,16 @@ describe Shoulda::Matchers::ActiveModel::ValidatePresenceOfMatcher do
     end
   end
 
+  context 'an active_resource model' do
+    context 'with the validation context' do
+      it 'does not raise an exception' do
+        expect {
+          active_resource_model.should validate_presence_of(:attr)
+        }.to_not raise_exception
+      end
+    end
+  end
+
   def matcher
     validate_presence_of(:attr)
   end
@@ -161,4 +171,10 @@ describe Shoulda::Matchers::ActiveModel::ValidatePresenceOfMatcher do
       end
     end.new
   end
+
+  def active_resource_model
+    define_active_resource_class :foo, :attr => :string do
+      validates_presence_of :attr
+    end.new
+  end
 end
diff --git a/spec/support/active_resource_builder.rb b/spec/support/active_resource_builder.rb
new file mode 100644
index 00000000..e7877217
--- /dev/null
+++ b/spec/support/active_resource_builder.rb
@@ -0,0 +1,27 @@
+module ActiveResourceBuilder
+  def self.included(example_group)
+    example_group.class_eval do
+      after do
+        ActiveSupport::Dependencies.clear
+      end
+    end
+  end
+
+  def define_active_resource_class(class_name, attributes = {}, &block)
+    define_class(class_name, ActiveResource::Base) do
+      schema do
+        attributes.each do |attr, type|
+          attribute attr, type
+        end
+      end
+
+      if block_given?
+        class_eval(&block)
+      end
+    end
+  end
+end
+
+RSpec.configure do |config|
+  config.include ActiveResourceBuilder
+end