refactor source pixiv test

refactor pixiv download tests
refactor upload test
refactor nico seiga test
refactor twitter tests

test/unit/sources/twitter_test.rb

@@ -4,12 +4,13 @@ module Sources
   class TwitterTest < ActiveSupport::TestCase
     def setup
       super
+      @record = false
       setup_vcr
     end
 
     context "The source site for a restricted twitter" do
       setup do
-        VCR.use_cassette("source-twitter-unit-test-2", :record => :once) do
+        VCR.use_cassette("sources-twitter-test/2", :record => @vcr_record_option) do
           @site = Sources::Site.new("https://mobile.twitter.com/Strangestone/status/556440271961858051")
           @site.get
         end
@@ -22,7 +23,7 @@ module Sources
 
     context "The source site for twitter" do
       setup do
-        VCR.use_cassette("source-twitter-unit-test-1", :record => :once) do
+        VCR.use_cassette("sources-twitter-test/1", :record => @vcr_record_option) do
           @site = Sources::Site.new("https://mobile.twitter.com/nounproject/status/540944400767922176")
           @site.get
         end