[subscribestar] extend fix + add test

some attachments are inside an element with an additional class besides
'doc_preview', e.g. 'class="doc_preview for_post"'

gallery_dl/extractor/subscribestar.py

@@ -11,6 +11,7 @@
 from .common import Extractor, Message
 from .. import text, util, exception
 from ..cache import cache
+import re
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.)?subscribestar\.(com|adult)"
 
@@ -100,7 +101,8 @@ class SubscribestarExtractor(Extractor):
         attachments = text.extr(
             html, 'class="uploads-docs"', 'class="post-edit_form"')
         if attachments:
-            for att in attachments.split('class="doc_preview"')[1:]:
+            for att in re.split(
+                    r'class="doc_preview[" ]', attachments)[1:]:
                 media.append({
                     "id"  : text.parse_int(text.extr(
                         att, 'data-upload-id="', '"')),
@@ -113,7 +115,8 @@ class SubscribestarExtractor(Extractor):
         audios = text.extr(
             html, 'class="uploads-audios"', 'class="post-edit_form"')
         if audios:
-            for audio in audios.split('class="audio_preview-data"')[1:]:
+            for audio in re.split(
+                    r'class="audio_preview-data[" ]', audios)[1:]:
                 media.append({
                     "id"  : text.parse_int(text.extr(
                         audio, 'data-upload-id="', '"')),