diff --git a/lib/stripe.rb b/lib/stripe.rb
index 17033965..1f61dbe4 100644
--- a/lib/stripe.rb
+++ b/lib/stripe.rb
@@ -314,7 +314,7 @@ module Stripe
     end
 
     def update_subscription(params)
-      response, api_key = Stripe.request(:post, subscription_url, @api_key)
+      response, api_key = Stripe.request(:post, subscription_url, @api_key, params)
       refresh_from({ :subscription => response }, api_key, true)
       subscription
     end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index abc1c9aa..81e6379e 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -97,6 +97,27 @@ def test_card(params={})
   }.merge(params)
 end
 
+#FIXME nested overrides would be better than hardcoding plan_id
+def test_subscription(plan_id="gold")
+  {
+    :current_period_end => 1308681468,
+    :status => "trialing",
+    :plan => {
+      :interval => "month",
+      :amount => 7500,
+      :trial_period_days => 30,
+      :object => "plan",
+      :identifier => plan_id
+    },
+    :current_period_start => 1308595038,
+    :start => 1308595038,
+    :object => "subscription",
+    :trial_start => 1308595038,
+    :trial_end => 1308681468,
+    :customer => "c_test_customer"
+  }
+end
+
 def test_invalid_api_key_error
   {
     "error" => {
diff --git a/test/test_stripe.rb b/test/test_stripe.rb
index d0546e4e..a6075342 100644
--- a/test/test_stripe.rb
+++ b/test/test_stripe.rb
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 require File.dirname(__FILE__) + '/test_helper.rb'
 require 'test/unit'
-require 'context'
+require 'shoulda'
 require 'mocha'
 require 'pp'
 require 'rest-client'
@@ -10,21 +10,21 @@ class TestStripeRuby < Test::Unit::TestCase
   include Mocha
 
   context "API Bindings" do
-    before do
+    setup do
       @mock = mock
       Stripe.mock_rest_client = @mock
     end
 
-    after do
+    teardown do
       Stripe.mock_rest_client = nil
     end
 
-    test "creating a new APIResource should not fetch over the network" do
+    should "creating a new APIResource should not fetch over the network" do
       @mock.expects(:get).never
       c = Stripe::Customer.new("someid")
     end
 
-    test "creating a new APIResource from a hash should not fetch over the network" do
+    should "creating a new APIResource from a hash should not fetch over the network" do
       @mock.expects(:get).never
       c = Stripe::Customer.construct_from({
         :id => "somecustomer",
@@ -33,26 +33,26 @@ class TestStripeRuby < Test::Unit::TestCase
       })
     end
 
-    test "setting an attribute should not cause a network request" do
+    should "setting an attribute should not cause a network request" do
       @mock.expects(:get).never
       @mock.expects(:post).never
       c = Stripe::Customer.new("test_customer");
       c.card = {:id => "somecard", :object => "card"}
     end
 
-    test "accessing id should not issue a fetch" do
+    should "accessing id should not issue a fetch" do
       @mock.expects(:get).never
       c = Stripe::Customer.new("test_customer");
       c.id
     end
 
-    test "not specifying api credentials should raise an exception" do
+    should "not specifying api credentials should raise an exception" do
       assert_raises Stripe::AuthenticationError do
         Stripe::Customer.new("test_customer").refresh
       end
     end
 
-    test "specifying invalid api credentials should raise an exception" do
+    should "specifying invalid api credentials should raise an exception" do
       Stripe.api_key="invalid"
       response = test_response(test_invalid_api_key_error, 401)
       assert_raises Stripe::AuthenticationError do
@@ -62,33 +62,33 @@ class TestStripeRuby < Test::Unit::TestCase
     end
 
     context "with valid credentials" do
-      before do
+      setup do
         Stripe.api_key="foo"
       end
 
-      after do
+      teardown do
         Stripe.api_key=nil
       end
 
-      test "requesting with a unicode ID should result in a request" do
+      should "requesting with a unicode ID should result in a request" do
         response = test_response(test_missing_id_error, 404)
         @mock.expects(:get).once.with("https://api.stripe.com/v1/customers/%E2%98%83").raises(RestClient::ExceptionWithResponse.new(response, 404))
         c = Stripe::Customer.new("☃")
         assert_raises(Stripe::InvalidRequestError) { c.refresh }
       end
 
-      test "requesting with no ID shuold result in an InvalidRequestError with no request" do
+      should "requesting with no ID shuold result in an InvalidRequestError with no request" do
         c = Stripe::Customer.new
         assert_raises(Stripe::InvalidRequestError) { c.refresh }
       end
 
-      test "loading an object should issue a GET request" do
+      should "loading an object should issue a GET request" do
         @mock.expects(:get).once.returns(test_response(test_customer))
         c = Stripe::Customer.new("test_customer")
         c.refresh
       end
 
-      test "using array accessors should be the same as the method interface" do
+      should "using array accessors should be the same as the method interface" do
         @mock.expects(:get).once.returns(test_response(test_customer))
         c = Stripe::Customer.new("test_customer")
         c.refresh
@@ -98,20 +98,20 @@ class TestStripeRuby < Test::Unit::TestCase
         assert_equal c.created, 12345
       end
 
-      test "accessing a property other than id or parent on an unfetched object should fetch it" do
+      should "accessing a property other than id or parent on an unfetched object should fetch it" do
         @mock.expects(:get).once.returns(test_response(test_customer))
         c = Stripe::Customer.new("test_customer")
         c.charges
       end
 
-      test "updating an object should issue a POST request with only the changed properties" do
+      should "updating an object should issue a POST request with only the changed properties" do
         @mock.expects(:post).with("https://api.stripe.com/v1/customers/c_test_customer", {:mnemonic => 'another_mn'}).once.returns(test_response(test_customer))
         c = Stripe::Customer.construct_from(test_customer)
         c.mnemonic = "another_mn"
         c.save
       end
 
-      test "updating should merge in returned properties" do
+      should "updating should merge in returned properties" do
         @mock.expects(:post).once.returns(test_response(test_customer))
         c = Stripe::Customer.new("c_test_customer")
         c.mnemonic = "another_mn"
@@ -119,7 +119,7 @@ class TestStripeRuby < Test::Unit::TestCase
         assert_equal false, c.livemode
       end
 
-      test "deleting should send no props and result in an object that has no props other deleted" do
+      should "deleting should send no props and result in an object that has no props other deleted" do
         @mock.expects(:get).never
         @mock.expects(:post).never
         @mock.expects(:delete).with("https://api.stripe.com/v1/customers/c_test_customer").once.returns(test_response({ "id" => "test_customer", "deleted" => true }))
@@ -133,13 +133,13 @@ class TestStripeRuby < Test::Unit::TestCase
         end
       end
 
-      test "loading an object with properties that have specific types should instantiate those classes" do
+      should "loading an object with properties that have specific types should instantiate those classes" do
         @mock.expects(:get).once.returns(test_response(test_charge))
         c = Stripe::Charge.retrieve("test_charge")
         assert c.card.kind_of?(Stripe::StripeObject) && c.card.object == 'card'
       end
 
-      test "loading all of an APIResource should return an array of recursively instantiated objects" do
+      should "loading all of an APIResource should return an array of recursively instantiated objects" do
         @mock.expects(:get).once.returns(test_response(test_charge_array))
         c = Stripe::Charge.all
         assert c.kind_of? Array
@@ -149,13 +149,13 @@ class TestStripeRuby < Test::Unit::TestCase
 
       context "charge tests" do
 
-        test "charges should be listable" do
+        should "charges should be listable" do
           @mock.expects(:get).once.returns(test_response(test_charge_array))
           c = Stripe::Charge.all
           assert c.kind_of? Array
         end
 
-        test "charges should be refundable" do
+        should "charges should be refundable" do
           @mock.expects(:get).never
           @mock.expects(:post).once.returns(test_response({:id => "ch_test_charge", :refunded => true}))
           c = Stripe::Charge.new("test_charge")
@@ -163,7 +163,7 @@ class TestStripeRuby < Test::Unit::TestCase
           assert c.refunded
         end
 
-        test "charges should not be deletable" do
+        should "charges should not be deletable" do
           assert_raises NoMethodError do
             @mock.expects(:get).once.returns(test_response(test_charge))
             c = Stripe::Charge.retrieve("test_charge")
@@ -171,7 +171,7 @@ class TestStripeRuby < Test::Unit::TestCase
           end
         end
 
-        test "charges should not be updateable" do
+        should "charges should not be updateable" do
           assert_raises NoMethodError do
             @mock.expects(:get).once.returns(test_response(test_charge))
             c = Stripe::Charge.new("test_charge")
@@ -181,13 +181,13 @@ class TestStripeRuby < Test::Unit::TestCase
           end
         end
 
-        test "charges should have Card objects associated with their Card property" do
+        should "charges should have Card objects associated with their Card property" do
           @mock.expects(:get).once.returns(test_response(test_charge))
           c = Stripe::Charge.retrieve("test_charge")
           assert c.card.kind_of?(Stripe::StripeObject) && c.card.object == 'card'
         end
 
-        test "execute should return a new, fully executed charge when passed correct parameters" do
+        should "execute should return a new, fully executed charge when passed correct parameters" do
           @mock.expects(:post).with('https://api.stripe.com/v1/charges', {
             :currency => 'usd', :amount => 100,
             :card => {:exp_year => 2012, :number => '4242424242424242', :exp_month => 11}
@@ -209,21 +209,21 @@ class TestStripeRuby < Test::Unit::TestCase
 
       context "customer tests" do
 
-        test "customers should be listable" do
+        should "customers should be listable" do
           @mock.expects(:get).once.returns(test_response(test_customer_array))
           c = Stripe::Customer.all
           assert c.kind_of? Array
           assert c[0].kind_of? Stripe::Customer
         end
 
-        test "customers should be deletable" do
+        should "customers should be deletable" do
           @mock.expects(:delete).once.returns(test_response(test_customer({:deleted => true})))
           c = Stripe::Customer.new("test_customer")
           c.delete
           assert c.deleted
         end
 
-        test "customers should be updateable" do
+        should "customers should be updateable" do
           @mock.expects(:get).once.returns(test_response(test_customer({:mnemonic => "foo"})))
           @mock.expects(:post).once.returns(test_response(test_customer({:mnemonic => "bar"})))
           c = Stripe::Customer.new("test_customer").refresh
@@ -233,18 +233,29 @@ class TestStripeRuby < Test::Unit::TestCase
           assert_equal c.mnemonic, "bar"
         end
 
-        test "customers should have Card objects associated with their active_ard property" do
+        should "customers should have Card objects associated with their active_ard property" do
           @mock.expects(:get).once.returns(test_response(test_customer))
           c = Stripe::Customer.retrieve("test_customer")
           assert c.active_card.kind_of?(Stripe::StripeObject) && c.active_card.object == 'card'
         end
 
-        test "create should return a new customer" do
+        should "create should return a new customer" do
           @mock.expects(:post).once.returns(test_response(test_customer))
           c = Stripe::Customer.create
           assert_equal "c_test_customer", c.id
         end
 
+        should "be able to update a customers subscription" do
+          @mock.expects(:get).once.returns(test_response(test_customer))
+          c = Stripe::Customer.retrieve("test_customer")
+
+          @mock.expects(:post).once.with("https://api.stripe.com/v1/customers/c_test_customer/subscription", {:plan => 'silver'}).returns(test_response(test_subscription('silver')))
+          s = c.update_subscription({:plan => 'silver'})
+
+          assert_equal 'subscription', s.object
+          assert_equal 'silver', s.plan.identifier
+        end
+
       end
 
       context "card tests" do
@@ -252,7 +263,7 @@ class TestStripeRuby < Test::Unit::TestCase
 
       context "error checking" do
 
-        test "404s should raise an InvalidRequestError" do
+        should "404s should raise an InvalidRequestError" do
           response = test_response(test_missing_id_error, 404)
           @mock.expects(:get).once.raises(RestClient::ExceptionWithResponse.new(response, 404))
 
@@ -269,7 +280,7 @@ class TestStripeRuby < Test::Unit::TestCase
           assert false #shouldn't get here
         end
 
-        test "5XXs should raise an APIError" do
+        should "5XXs should raise an APIError" do
           response = test_response(test_api_error, 500)
           @mock.expects(:get).once.raises(RestClient::ExceptionWithResponse.new(response, 500))
 
@@ -284,7 +295,7 @@ class TestStripeRuby < Test::Unit::TestCase
           assert false #shouldn't get here
         end
 
-        test "402s should raise a CardError" do
+        should "402s should raise a CardError" do
           response = test_response(test_invalid_exp_year_error, 402)
           @mock.expects(:get).once.raises(RestClient::ExceptionWithResponse.new(response, 402))