diff --git a/tests/test_audio.py b/tests/test_audio.py
index c50025ffd..d66a89f91 100644
--- a/tests/test_audio.py
+++ b/tests/test_audio.py
@@ -148,7 +148,7 @@ class AudioTest(BaseTest, unittest.TestCase):
         self.assertEqual(audio.performer, self.performer)
         self.assertEqual(audio.title, self.title)
         self.assertEqual(audio.mime_type, self.mime_type)
-        self.assertEqual(audio.file_size, 36320)
+        self.assertEqual(audio.file_size, self.file_size)
 
     def test_send_audio_resend(self):
         """Test telegram.Bot sendAudio method"""
diff --git a/tests/test_document.py b/tests/test_document.py
index ea48f136b..494bf9987 100644
--- a/tests/test_document.py
+++ b/tests/test_document.py
@@ -34,7 +34,7 @@ class DocumentTest(BaseTest, unittest.TestCase):
     def setUp(self):
         self.document_file = open('tests/data/telegram.png', 'rb')
         self.document_file_id = 'BQADAQADpAADHyP1B04ipZxJTe2BAg'
-        self.document_file_url = 'http://dummyimage.com/600x400/000/fff.gif&text=telegram'
+        self.document_file_url = 'https://github.com/python-telegram-bot/python-telegram-bot/blob/master/tests/data/telegram.gif'
         self.thumb = {'width': 90,
                       'height': 90,
                       'file_id': 'BQADAQADoQADHyP1B0mzJMVyzcB0Ag',
@@ -98,7 +98,7 @@ class DocumentTest(BaseTest, unittest.TestCase):
         self.assertTrue(isinstance(document.thumb, telegram.PhotoSize))
         self.assertEqual(document.file_name, 'fff.gif')
         self.assertEqual(document.mime_type, 'image/gif')
-        self.assertEqual(document.file_size, 3878)
+        self.assertEqual(document.file_size, self.file_size)
 
     def test_send_document_resend(self):
         """Test telegram.Bot sendDocument method"""
diff --git a/tests/test_video.py b/tests/test_video.py
index 20aa2cc3d..85e7cbc70 100644
--- a/tests/test_video.py
+++ b/tests/test_video.py
@@ -158,7 +158,7 @@ class VideoTest(BaseTest, unittest.TestCase):
         self.assertEqual(video.duration, self.duration)
         self.assertEqual(video.thumb, None)
         self.assertEqual(video.mime_type, '')
-        self.assertEqual(video.file_size, 36315)
+        self.assertEqual(video.file_size, self.file_size)
 
         self.assertEqual(message.caption, self.caption)
 
diff --git a/tests/test_voice.py b/tests/test_voice.py
index 44ed0c15e..da9edd891 100644
--- a/tests/test_voice.py
+++ b/tests/test_voice.py
@@ -126,7 +126,7 @@ class VoiceTest(BaseTest, unittest.TestCase):
         self.assertNotEqual(voice.file_id, '')
         self.assertEqual(voice.duration, self.duration)
         self.assertEqual(voice.mime_type, self.mime_type)
-        self.assertEqual(voice.file_size, 36316)
+        self.assertEqual(voice.file_size, self.file_size)
 
     def test_send_voice_resend(self):
         """Test telegram.Bot sendVoice method"""