diff --git a/gallery_dl/extractor/__init__.py b/gallery_dl/extractor/__init__.py
index b42e5c47..ec39961e 100644
--- a/gallery_dl/extractor/__init__.py
+++ b/gallery_dl/extractor/__init__.py
@@ -97,7 +97,7 @@ def extractors():
 
 class blacklist():
     """Context Manager to blacklist extractor modules"""
-    def __init__(self, *categories):
+    def __init__(self, categories):
         self.categories = categories
 
     def __enter__(self):
diff --git a/gallery_dl/extractor/flickr.py b/gallery_dl/extractor/flickr.py
index fdc46c2c..38a3ce36 100644
--- a/gallery_dl/extractor/flickr.py
+++ b/gallery_dl/extractor/flickr.py
@@ -9,7 +9,7 @@
 """Extract images from https://www.flickr.com/"""
 
 from .common import Extractor, Message
-from .. import text, util, oauth, exception
+from .. import text, util, exception
 import urllib.parse
 
 
@@ -249,7 +249,7 @@ class FlickrAPI():
         token = extractor.config("access-token")
         token_secret = extractor.config("access-token-secret")
         if token and token_secret:
-            self.session = oauth.OAuthSession(
+            self.session = util.OAuthSession(
                 extractor.session,
                 self.API_KEY, self.API_SECRET, token, token_secret)
             self.API_KEY = None
diff --git a/gallery_dl/extractor/oauthhelper.py b/gallery_dl/extractor/oauthhelper.py
index 29eeb53a..64deb198 100644
--- a/gallery_dl/extractor/oauthhelper.py
+++ b/gallery_dl/extractor/oauthhelper.py
@@ -10,7 +10,7 @@
 
 from .common import Extractor, Message
 from . import reddit, flickr
-from .. import oauth
+from .. import util
 import os
 import urllib.parse
 
@@ -80,7 +80,7 @@ class OAuthReddit(OAuthBase):
         self.session.headers["User-Agent"] = reddit.RedditAPI.USER_AGENT
         self.client_id = reddit.RedditAPI.CLIENT_ID
         self.state = "gallery-dl:{}:{}".format(
-            self.subcategory, oauth.OAuthSession.nonce(8))
+            self.subcategory, util.OAuthSession.nonce(8))
 
     def items(self):
         yield Message.Version, 1
@@ -128,7 +128,7 @@ class OAuthFlickr(OAuthBase):
 
     def __init__(self, match):
         OAuthBase.__init__(self)
-        self.session = oauth.OAuthSession(
+        self.session = util.OAuthSession(
             self.session,
             flickr.FlickrAPI.API_KEY, flickr.FlickrAPI.API_SECRET
         )
diff --git a/gallery_dl/extractor/recursive.py b/gallery_dl/extractor/recursive.py
index 0592bf42..d7b33419 100644
--- a/gallery_dl/extractor/recursive.py
+++ b/gallery_dl/extractor/recursive.py
@@ -10,7 +10,7 @@
 
 import re
 from .common import Extractor, Message
-from .. import extractor, adapter
+from .. import extractor, adapter, util
 
 
 class RecursiveExtractor(Extractor):
@@ -27,8 +27,10 @@ class RecursiveExtractor(Extractor):
         self.url = match.group(1)
 
     def items(self):
+        blist = self.config(
+            "blacklist", ("directlink",) + util.SPECIAL_EXTRACTORS)
         page = self.request(self.url).text
         yield Message.Version, 1
-        with extractor.blacklist("directlink"):
+        with extractor.blacklist(blist):
             for match in re.finditer(r"https?://[^\s\"']+", page):
                 yield Message.Queue, match.group(0)
diff --git a/gallery_dl/extractor/reddit.py b/gallery_dl/extractor/reddit.py
index bd3dcacd..589c4a46 100644
--- a/gallery_dl/extractor/reddit.py
+++ b/gallery_dl/extractor/reddit.py
@@ -9,7 +9,7 @@
 """Extract images subreddits at https://reddit.com/"""
 
 from .common import Extractor, Message
-from .. import text, extractor, exception
+from .. import text, util, extractor, exception
 from ..cache import cache
 import time
 import re
@@ -31,7 +31,7 @@ class RedditExtractor(Extractor):
         depth = 0
 
         yield Message.Version, 1
-        with extractor.blacklist("reddit"):
+        with extractor.blacklist(("reddit",) + util.SPECIAL_EXTRACTORS):
             while True:
                 extra = []
                 for url in self._urls(submissions):
diff --git a/gallery_dl/oauth.py b/gallery_dl/oauth.py
deleted file mode 100644
index a27da285..00000000
--- a/gallery_dl/oauth.py
+++ /dev/null
@@ -1,54 +0,0 @@
-# -*- coding: utf-8 -*-
-
-# Copyright 2017 Mike Fährmann
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-
-"""Utility classes for OAuth 1.0"""
-
-import hmac
-import time
-import base64
-import random
-import string
-import hashlib
-import urllib.parse
-
-
-class OAuthSession():
-    """Minimal wrapper for requests.session objects to support OAuth 1.0"""
-    def __init__(self, session, consumer_key, consumer_secret,
-                 token=None, token_secret=None):
-        self.session = session
-        self.consumer_secret = consumer_secret
-        self.token_secret = token_secret or ""
-        self.params = session.params
-        self.params["oauth_consumer_key"] = consumer_key
-        self.params["oauth_token"] = token
-        self.params["oauth_signature_method"] = "HMAC-SHA1"
-        self.params["oauth_version"] = "1.0"
-
-    def get(self, url, params):
-        params.update(self.params)
-        params["oauth_nonce"] = self.nonce(16)
-        params["oauth_timestamp"] = int(time.time())
-        params["oauth_signature"] = self.signature(url, params)
-        return self.session.get(url, params=params)
-
-    def signature(self, url, params):
-        """Generate 'oauth_signature' value"""
-        query = urllib.parse.urlencode(sorted(params.items()))
-        message = self.concat("GET", url, query).encode()
-        key = self.concat(self.consumer_secret, self.token_secret).encode()
-        signature = hmac.new(key, message, hashlib.sha1).digest()
-        return base64.b64encode(signature).decode()
-
-    @staticmethod
-    def concat(*args):
-        return "&".join(urllib.parse.quote(item, "") for item in args)
-
-    @staticmethod
-    def nonce(N, alphabet=string.ascii_letters):
-        return "".join(random.choice(alphabet) for _ in range(N))
diff --git a/gallery_dl/util.py b/gallery_dl/util.py
index 6ae5975d..c51c2349 100644
--- a/gallery_dl/util.py
+++ b/gallery_dl/util.py
@@ -10,6 +10,13 @@
 
 import os
 import sys
+import hmac
+import time
+import base64
+import random
+import string
+import hashlib
+import urllib.parse
 from . import config, text, exception
 
 
@@ -75,19 +82,19 @@ def bdecode(data, alphabet="0123456789"):
 
 def code_to_language(code, default="English"):
     """Map an ISO 639-1 language code to its actual name"""
-    return codes.get(code.lower(), default)
+    return CODES.get(code.lower(), default)
 
 
 def language_to_code(lang, default="en"):
     """Map a language name to its ISO 639-1 code"""
     lang = lang.capitalize()
-    for code, language in codes.items():
+    for code, language in CODES.items():
         if language == lang:
             return code
     return default
 
 
-codes = {
+CODES = {
     "ar": "Arabic",
     "cs": "Czech",
     "da": "Danish",
@@ -117,6 +124,8 @@ codes = {
     "zh": "Chinese",
 }
 
+SPECIAL_EXTRACTORS = ("oauth", "recursive", "test")
+
 
 class RangePredicate():
     """Predicate; is True if the current index is in the given range"""
@@ -224,3 +233,40 @@ class PathFormat():
     def adjust_path(path):
         """Enable longer-than-260-character paths on windows"""
         return "\\\\?\\" + os.path.abspath(path) if os.name == "nt" else path
+
+
+class OAuthSession():
+    """Minimal wrapper for requests.session objects to support OAuth 1.0"""
+    def __init__(self, session, consumer_key, consumer_secret,
+                 token=None, token_secret=None):
+        self.session = session
+        self.consumer_secret = consumer_secret
+        self.token_secret = token_secret or ""
+        self.params = session.params
+        self.params["oauth_consumer_key"] = consumer_key
+        self.params["oauth_token"] = token
+        self.params["oauth_signature_method"] = "HMAC-SHA1"
+        self.params["oauth_version"] = "1.0"
+
+    def get(self, url, params):
+        params.update(self.params)
+        params["oauth_nonce"] = self.nonce(16)
+        params["oauth_timestamp"] = int(time.time())
+        params["oauth_signature"] = self.signature(url, params)
+        return self.session.get(url, params=params)
+
+    def signature(self, url, params):
+        """Generate 'oauth_signature' value"""
+        query = urllib.parse.urlencode(sorted(params.items()))
+        message = self.concat("GET", url, query).encode()
+        key = self.concat(self.consumer_secret, self.token_secret).encode()
+        signature = hmac.new(key, message, hashlib.sha1).digest()
+        return base64.b64encode(signature).decode()
+
+    @staticmethod
+    def concat(*args):
+        return "&".join(urllib.parse.quote(item, "") for item in args)
+
+    @staticmethod
+    def nonce(N, alphabet=string.ascii_letters):
+        return "".join(random.choice(alphabet) for _ in range(N))
diff --git a/scripts/build_testresult_db.py b/scripts/build_testresult_db.py
index 0570f2e7..ecaf2747 100755
--- a/scripts/build_testresult_db.py
+++ b/scripts/build_testresult_db.py
@@ -9,7 +9,7 @@ sys.path.insert(0, os.path.realpath(ROOTDIR))
 from gallery_dl import extractor, job, config
 
 tests = [
-   ([url[0] for url in extr.test], extr)
+   ([url[0] for url in extr.test if url[1]], extr)
    for extr in extractor.extractors()
    if hasattr(extr, "test")
 ]