return Instapaper::Credentials instead of a hash from oauth

lib/instapaper/api/oauth.rb

@@ -1,3 +1,4 @@
+require 'instapaper/credentials'
 require 'instapaper/http/qline_parser'
 
 module Instapaper
@@ -7,7 +8,9 @@ module Instapaper
       # Gets an OAuth access token for a user.
       def access_token(username, password)
         response = perform_post_with_unparsed_response('/api/1/oauth/access_token', x_auth_username: username, x_auth_password: password, x_auth_mode: 'client_auth')
-        QLineParser.parse(response)
+        parsed_response = QLineParser.parse(response)
+        fail Instapaper::Error::OAuthError, parsed_response[:error] if parsed_response.key?(:error)
+        Instapaper::Credentials.new(parsed_response)
       end
     end
   end

lib/instapaper/credentials.rb

@@ -0,0 +1,12 @@
+require 'virtus'
+
+module Instapaper
+  class Credentials
+    include Virtus.value_object
+
+    values do
+      attribute :oauth_token, String
+      attribute :oauth_token_secret, String
+    end
+  end
+end

lib/instapaper/error.rb

@@ -7,6 +7,7 @@ module Instapaper
     BookmarkError = Class.new(self)
     FolderError = Class.new(self)
     HighlightError = Class.new(self)
+    OAuthError = Class.new(self)
 
     ERRORS = {
       1040 => 'Rate-limit exceeded',

lib/instapaper/http/qline_parser.rb

@@ -1,9 +1,13 @@
+require 'instapaper/utils'
+
 module Instapaper
   class QLineParser
+    extend Instapaper::Utils
+
     def self.parse(response)
       values = response.split('&').map { |part| part.split('=') }.flatten
       values.unshift('error') if values.length == 1
-      Hash[*values]
+      symbolize_keys!(Hash[*values])
     end
   end
 end

lib/instapaper/http/request.rb

@@ -5,10 +5,12 @@ require 'net/https'
 require 'openssl'
 require 'instapaper/error'
 require 'instapaper/http/headers'
+require 'instapaper/utils'
 
 module Instapaper
   module HTTP
     class Request
+      include Instapaper::Utils
       BASE_URL = 'https://www.instapaper.com'
       attr_accessor :client, :headers, :multipart, :options, :path,
                     :rate_limit, :request_method, :uri
@@ -63,19 +65,6 @@ module Instapaper
           response.to_s
         end
       end
-
-      def symbolize_keys!(object)
-        if object.is_a?(Array)
-          object.each_with_index do |val, index|
-            object[index] = symbolize_keys!(val)
-          end
-        elsif object.is_a?(Hash)
-          object.keys.each do |key|
-            object[key.to_sym] = symbolize_keys!(object.delete(key))
-          end
-        end
-        object
-      end
     end
   end
 end

lib/instapaper/utils.rb

@@ -0,0 +1,18 @@
+module Instapaper
+  module Utils
+    private
+
+    def symbolize_keys!(object)
+      if object.is_a?(Array)
+        object.each_with_index do |val, index|
+          object[index] = symbolize_keys!(val)
+        end
+      elsif object.is_a?(Hash)
+        object.keys.each do |key|
+          object[key.to_sym] = symbolize_keys!(object.delete(key))
+        end
+      end
+      object
+    end
+  end
+end

spec/instapaper/api/oauth_spec.rb

@@ -19,15 +19,13 @@ describe Instapaper::Client::OAuth do
 
     it 'returns the a hash containing an oauth token and secret' do
       tokens = client.access_token('ohai', 'p455w0rd')
-      expect(tokens).to be_a Hash
+      expect(tokens).to be_an Instapaper::Credentials
-      expect(tokens.key?('oauth_token')).to be true
-      expect(tokens.key?('oauth_token_secret')).to be true
     end
 
     it 'returns a hash containing the error on invalid credentials' do
-      tokens = client.access_token('inval1d', 'cr3dentials')
+      expect {
-      expect(tokens).to be_a Hash
+        client.access_token('inval1d', 'cr3dentials')
-      expect(tokens.key?('error')).to be true
+      }.to raise_error(Instapaper::Error::OAuthError)
     end
   end
 end