refactor twitter service to handle cards (fixes #3031)

test/unit/sources/twitter_test.rb

@@ -2,6 +2,39 @@ require 'test_helper'
 
 module Sources
   class TwitterTest < ActiveSupport::TestCase
+    context "A video" do
+      setup do
+        @site = Sources::Site.new("https://twitter.com/CincinnatiZoo/status/859073537713328129")
+        @site.get
+      end
+
+      should "get the image url" do
+        assert_equal("https://video.twimg.com/ext_tw_video/859073467769126913/pu/vid/1280x720/cPGgVROXHy3yrK6u.mp4", @site.image_url)
+      end
+    end
+
+    context "An animated gif" do
+      setup do
+        @site = Sources::Site.new("https://twitter.com/DaniStrawberry1/status/859435334765088769")
+        @site.get
+      end
+
+      should "get the image url" do
+        assert_equal("https://video.twimg.com/tweet_video/C-1Tns7WsAAqvqn.mp4", @site.image_url)
+      end
+    end
+
+    context "A twitter summary card" do
+      setup do
+        @site = Sources::Site.new("https://twitter.com/NatGeo/status/787654447937847296")
+        @site.get
+      end
+
+      should "get the image url" do
+        assert_equal("http://yourshot.nationalgeographic.com/u/fQYSUbVfts-T7odkrFJckdiFeHvab0GWOfzhj7tYdC0uglagsDcUxj3Tf7HBF3kZEj7S5m-zeDmZP6DBxBJlyJX_1mFp-hGf4JPt97xp0QJkwf4po1MmnZH73WC3a2Pa1Ky62C-v0cYXTur3-QwD3Pz5UI_cKIi81GABTXII8VwKUopxlNW2MYAR8kPYU2IoUhOjlvVefNcLYI74J-0IpI4tHDXE/", @site.image_url)
+      end
+    end
+
     context "The source site for a restricted twitter" do
       setup do
         @site = Sources::Site.new("https://mobile.twitter.com/Strangestone/status/556440271961858051")