Adds retrieve payment methods customer endpoint

lib/stripe_mock/request_handlers/customers.rb

@@ -10,6 +10,7 @@ def Customers.included(klass)
         klass.add_handler 'get /v1/customers',                      :list_customers
         klass.add_handler 'get /v1/customers/search',               :search_customers
         klass.add_handler 'delete /v1/customers/([^/]*)/discount',  :delete_customer_discount
+        klass.add_handler 'get /v1/customers/([^/]+)/payment_methods/([^/]+)', :retrieve_payment_method
       end
 
       def new_customer(route, method_url, params, headers)
@@ -160,6 +161,17 @@ def delete_customer_discount(route, method_url, params, headers)
 
         cus
       end
+
+      def retrieve_payment_method(route, method_url, params, headers)
+        stripe_account = headers && headers[:stripe_account] || Stripe.api_key
+
+        route =~ method_url
+        customer_id, payment_method_id = $1, $2
+        customer = assert_existence(:customer, customer_id, customers[stripe_account][customer_id])
+        payment_method = customer[:sources][:data].find { |source| source[:id] == payment_method_id }
+        assert_existence(:payment_method, payment_method_id, payment_method)
+        payment_method
+      end
     end
   end
 end

lib/stripe_mock/request_handlers/payment_methods.rb

@@ -58,11 +58,19 @@ def attach_payment_method(route, method_url, params, headers)
         allowed_params = [:customer]
 
         id = method_url.match(route)[1]
-
-        assert_existence :customer, params[:customer], customers[stripe_account][params[:customer]]
-
+  
+        customer = assert_existence :customer, params[:customer], customers[stripe_account][params[:customer]]
+  
         payment_method = assert_existence :payment_method, id, payment_methods[id]
         payment_methods[id] = Util.rmerge(payment_method, params.select { |k, _v| allowed_params.include?(k) })
+
+        customer[:sources] ||= { data: [], total_count: 0 }
+
+        unless customer[:sources][:data].any? { |source| source[:id] == id }
+          customer[:sources][:data] << payment_methods[id]
+          customer[:sources][:total_count] += 1
+        end
+
         payment_methods[id].clone
       end
 

spec/shared_stripe_examples/customer_examples.rb

@@ -535,4 +535,26 @@ def gen_card_tk
     customer = Stripe::Customer.retrieve("test_customer_update")
     expect(customer.discount).to be nil
   end
+
+  it "retrieves a stripe customers payment method" do
+    payment_method = Stripe::PaymentMethod.create({
+      type: 'card',
+      card: {
+        number: '4242424242424242',
+        exp_month: 12,
+        exp_year: 2024,
+        cvc: 123
+      }
+    })
+
+    customer = Stripe::Customer.create({
+      email: 'johnny@appleseed.com',
+      description: "a description"
+    })
+
+    payment_method.attach(customer: customer.id)
+
+    retrieved_payment_method = Stripe::Customer.retrieve_payment_method(customer.id, payment_method.id)
+    expect(retrieved_payment_method.id).to eq(payment_method.id)
+  end
 end