I solved my problem by tweeting the original URL on my timeline, then reading its shortened version, and finally running a query using the shortened URL.
Here is the Python code I used:
twitter_api = twitter.Twitter(auth = auth)
# searching for tweets
video_list = ["HdwMY2Fa7G4","FuqLui0_EF8","ZLUSg1_-o4c",
"jvN5OwkwwmE","D2H839E2PIw","94wmdh23JsQ",
"MIXuXnnW4io","9Jo0uk9ewWQ","9eBHdFpmpHs",
"czr4nUEF77s","Q-P9ygH6T20","SWnXj8Nkpic",
"5IgvJ7mEl4c","grZPvHb0yA8","Gwk6FmiAKCo",
"vCub9qk4vTk","PX0qDfYNykc","HLz_4NVSO6c",
"rTB5kwmv9D4","gXwZ3dbIhjw"]
k = 0 # counter
for vid in video_list:
k += 1
# settings
count = 10
video_url = 'https://www.youtube.com/watch?v='+vid
# tweet video URL in my timeline
twitter_api.statuses.update(status = video_url)
# retrieve shortened URL from my last tweet
my_account = 'ibbessi'
args = {'count' : 1}
timeline = twitter_api.statuses.user_timeline(screen_name = my_account, **args)
shortened_url = timeline[0]['text']
print '# ', str(k), '\noriginal URL:', video_url, '\nshortened URL:', shortened_url, '\n'
# search the shortened URL
search_results = twitter_api.search.tweets(q = shortened_url, count = count)
statuses = search_results['statuses']
# output shortened URL
print 'I have found ' + str(len(statuses)) + ' tweet(s) with video ' + shortened_url + '\n'
for i in range(0,len(statuses)):
print '#', str(i+1), '\nTEXT: ' , statuses[i]['text'], '\nUSER: ', statuses[i]['user']['name'], '\nRT COUNT: ', statuses[i]['retweet_count'], '\nDATE: ', statuses[i]['created_at'],'\n'