Merge pull request #20 from williamhogman/master

Add method for changing payment source for subscriptions

lib/stripe/subscriptions.ex

@@ -184,6 +184,21 @@ defmodule Stripe.Subscriptions do
     end
   end
 
+  @doc """
+  Changes the payment source for a subscription.
+
+  #Example
+  ```
+  source = [object: "card", number: "4111111111111111", exp_month: 01, exp_year: 2018, cvc: 123]
+  Stripe.Subscriptions.change_payment_source("customer_id", "subscription_id", source)
+  ```
+  """
+  def change_payment_source(customer_id, sub_id, source) do
+    data = [source: source]
+    Stripe.make_request(:post, "#{@endpoint}/#{customer_id}/subscriptions/#{sub_id}", data)
+    |> Stripe.Util.handle_stripe_response
+  end
+
   @max_fetch_size 100
   @doc """
   List all subscriptions.

test/stripe/subscription_test.exs

@@ -141,6 +141,20 @@ defmodule Stripe.SubscriptionTest do
     end
   end
 
+  @tag disable: false
+  test "Change creditcards works", %{customer: c, sub2: sub2} do
+    source = [
+      object: "card",
+      number: "4012888888881881",
+      exp_year: "20",
+      exp_month: "12",
+    ]
+    case Stripe.Subscriptions.change_payment_source(c.id, sub2.id, source) do
+      {:ok, res} ->
+        assert res[:status] == "active"
+      {:error, err} -> flunk err
+    end
+  end
   @tag disabled: false
   test "Cancel all works", %{customer: customer,  sub1: _, sub2: _} do
     Stripe.Subscriptions.cancel_all customer.id, []