tests: don't run the test if any of the extractors listed in the 'add_ie' field is marked as not working

youtube_dl/extractor/generic.py

@@ -33,6 +33,7 @@ class GenericIE(InfoExtractor):
         },
         # embedded vimeo video
         {
+            u'add_ie': ['Vimeo'],
             u'url': u'http://skillsmatter.com/podcast/home/move-semanticsperfect-forwarding-and-rvalue-references',
             u'file': u'22444065.mp4',
             u'md5': u'2903896e23df39722c33f015af0666e2',
@@ -44,6 +45,7 @@ class GenericIE(InfoExtractor):
         },
         # bandcamp page with custom domain
         {
+            u'add_ie': ['Bandcamp'],
             u'url': u'http://bronyrock.com/track/the-pony-mash',
             u'file': u'3235767654.mp3',
             u'info_dict': {

youtube_dl/extractor/mtv.py

@@ -26,6 +26,7 @@ class MTVIE(InfoExtractor):
             },
         },
         {
+            u'add_ie': ['Vevo'],
             u'url': u'http://www.mtv.com/videos/taylor-swift/916187/everything-has-changed-ft-ed-sheeran.jhtml',
             u'file': u'USCJY1331283.mp4',
             u'md5': u'73b4e7fcadd88929292fe52c3ced8caf',

youtube_dl/extractor/slashdot.py

@@ -7,6 +7,7 @@ class SlashdotIE(InfoExtractor):
     _VALID_URL = r'https?://tv.slashdot.org/video/\?embed=(?P<id>.*?)(&|$)'
 
     _TEST = {
+        u'add_ie': ['Ooyala'],
         u'url': u'http://tv.slashdot.org/video/?embed=JscHMzZDplD0p-yNLOzTfzC3Q3xzJaUz',
         u'file': u'JscHMzZDplD0p-yNLOzTfzC3Q3xzJaUz.mp4',
         u'md5': u'd2222e7a4a4c1541b3e0cf732fb26735',

youtube_dl/extractor/weibo.py

@@ -13,6 +13,7 @@ class WeiboIE(InfoExtractor):
     _VALID_URL = r'https?://video\.weibo\.com/v/weishipin/t_(?P<id>.+?)\.htm'
 
     _TEST = {
+        u'add_ie': ['Sina'],
         u'url': u'http://video.weibo.com/v/weishipin/t_zjUw2kZ.htm',
         u'file': u'98322879.flv',
         u'info_dict': {