diff --git a/dosagelib/http.py b/dosagelib/http.py
index a324863e0..e8a6b56b6 100644
--- a/dosagelib/http.py
+++ b/dosagelib/http.py
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2019 Tobias Gruetzmacher
-from collections import defaultdict
-from random import uniform
-from time import time, sleep
+# Copyright (C) 2019-2020 Tobias Gruetzmacher
+import collections
+import random
+import time
 
 import requests
 from requests.adapters import HTTPAdapter
@@ -38,7 +38,7 @@ class Session(requests.Session):
         self.mount('https://', HTTPAdapter(max_retries=retry))
         self.headers.update({'User-Agent': UserAgent})
 
-        self.throttles = defaultdict(lambda: RandomThrottle(0.0, 0.3))
+        self.throttles = collections.defaultdict(lambda: RandomThrottle())
 
     def send(self, request, **kwargs):
         if 'timeout' not in kwargs:
@@ -56,16 +56,16 @@ class Session(requests.Session):
 
 
 class RandomThrottle(object):
-    def __init__(self, th_min, th_max):
+    def __init__(self, th_min=0.0, th_max=0.3):
         self.th_min = th_min
         self.th_max = th_max
-        self.next = time()
+        self.next = time.time()
 
     def delay(self):
-        d = self.next - time()
+        d = self.next - time.time()
         if d > 0:
-            sleep(d)
-        self.next = time() + uniform(self.th_min, self.th_max)
+            time.sleep(d)
+        self.next = time.time() + random.uniform(self.th_min, self.th_max)
 
 
 # A default session for cookie and connection sharing
diff --git a/tests/conftest.py b/tests/conftest.py
index 1384cc5f5..156c81613 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,12 +1,12 @@
 # -*- coding: utf-8 -*-
-# Copyright (C) 2019 Tobias Gruetzmacher
+# Copyright (C) 2019-2020 Tobias Gruetzmacher
 import time
 
 import pytest
 
 
-@pytest.fixture
-def nosleep(monkeypatch):
+@pytest.fixture()
+def _nosleep(monkeypatch):
 
     def sleep(seconds):
         pass
diff --git a/tests/modules/conftest.py b/tests/modules/conftest.py
index 53caef723..b32584359 100644
--- a/tests/modules/conftest.py
+++ b/tests/modules/conftest.py
@@ -15,29 +15,25 @@ def get_test_scrapers():
     """Return scrapers that should be tested."""
     if "TESTALL" in os.environ:
         # test all comics (this will take some time)
-        scrapers = scraper.get_scrapers()
+        return scraper.get_scrapers()
+    if 'TESTCOMICS' in os.environ:
+        scraper_pattern = re.compile(os.environ['TESTCOMICS'])
     else:
-        if 'TESTCOMICS' in os.environ:
-            scraper_pattern = re.compile(os.environ['TESTCOMICS'])
-        else:
-            # Get limited number of scraper tests on Travis builds to make it
-            # faster
-            testscrapernames = [
-                # "classic" _BasicScraper
-                'AbstruseGoose',
-                # complex _ParserScraper
-                'GoComics/CalvinAndHobbes',
-                # _WordPressScraper
-                'GrrlPower'
-            ]
-            scraper_pattern = re.compile('^(' + '|'.join(testscrapernames) +
-                                         ')$')
-
-        scrapers = [
-            scraperobj for scraperobj in scraper.get_scrapers()
-            if scraper_pattern.match(scraperobj.name)
+        # Get limited number of scraper tests as default
+        testscrapernames = [
+            # "classic" _BasicScraper
+            'AbstruseGoose',
+            # complex _ParserScraper
+            'GoComics/CalvinAndHobbes',
+            # _WordPressScraper
+            'GrrlPower'
         ]
-    return scrapers
+        scraper_pattern = re.compile('^(' + '|'.join(testscrapernames) + ')$')
+
+    return [
+        scraperobj for scraperobj in scraper.get_scrapers()
+        if scraper_pattern.match(scraperobj.name)
+    ]
 
 
 def pytest_generate_tests(metafunc):
diff --git a/tests/test_dosage.py b/tests/test_dosage.py
index 0504ef026..41e1f02a8 100644
--- a/tests/test_dosage.py
+++ b/tests/test_dosage.py
@@ -26,7 +26,7 @@ def cmd_err(*options):
     assert cmd(*options) == 1
 
 
-@pytest.mark.usefixtures("nosleep")
+@pytest.mark.usefixtures("_nosleep")
 class TestDosage(object):
     """Test the dosage commandline client."""
 
diff --git a/tests/test_modules.py b/tests/test_modules.py
index 9faa15674..4b0d6c3e0 100644
--- a/tests/test_modules.py
+++ b/tests/test_modules.py
@@ -14,7 +14,7 @@ def cmd(*options):
     assert dosagelib.cmd.main(("--allow-multiple",) + options) == 0
 
 
-@pytest.mark.usefixtures("nosleep")
+@pytest.mark.usefixtures("_nosleep")
 class TestModules(object):
     """Test that specific comic modules work correctly."""
 
diff --git a/tests/test_scraper.py b/tests/test_scraper.py
index fb7b5a90a..8591ab7b0 100644
--- a/tests/test_scraper.py
+++ b/tests/test_scraper.py
@@ -22,5 +22,5 @@ class TestScraper(object):
         assert len(result) > 1
 
     def test_find_scrapers_error(self):
-        with pytest.raises(ValueError):
-            scraper.find_scrapers("")
+        with pytest.raises(ValueError, match='empty comic name'):
+            scraper.find_scrapers('')
diff --git a/tests/test_util.py b/tests/test_util.py
index a533dde93..b69aa33de 100644
--- a/tests/test_util.py
+++ b/tests/test_util.py
@@ -22,7 +22,7 @@ class TestRegex(object):
 
     ValuePrefix = '/bla/'
 
-    @pytest.mark.parametrize("tag,value,domatch", [
+    @pytest.mark.parametrize(('tag', 'value', 'domatch'), [
         ('<img src="%s">', ValuePrefix + 'foo', True),
         ('< img  src = "%s" >', ValuePrefix, True),
         ('<img class="prev" src="%s">', ValuePrefix + '...', True),
diff --git a/tox.ini b/tox.ini
index b41cb4a01..a191c993a 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,8 +28,11 @@ commands =
           --tee --output-file={toxworkdir}/flake8.log
 deps =
     flake8
+    flake8-2020
     flake8-coding
     flake8-future-import
+    flake8-pytest
+    flake8-pytest-style
 
 [flake8]
 # we aim for 79, but this suppresses warnings for now...