diff --git a/tests/mockserver.py b/tests/mockserver.py
index 43378b1c..0bf56cc9 100644
--- a/tests/mockserver.py
+++ b/tests/mockserver.py
@@ -18,14 +18,14 @@ def get_ephemeral_port():
 
 
 class MockScrapydServer:
-    def __init__(self, authentication=None):
-        self.authentication = authentication
+    def __init__(self, username=None, password=None):
+        self.username = username
+        self.password = password
 
-    def __enter__(self, authentication=None):
-        """Launch Scrapyd application object with ephemeral port"""
+    def __enter__(self):
         command = [sys.executable, os.path.join(BASEDIR, "start_mock_app.py"), get_ephemeral_port()]
-        if self.authentication is not None:
-            command.append("--auth=" + self.authentication)
+        if self.username and self.password:
+            command.extend([f"--username={self.username}", f"--password={self.password}"])
 
         self.process = Popen(command, stdout=PIPE)
 
diff --git a/tests/start_mock_app.py b/tests/start_mock_app.py
index 61f1636c..01e9ad20 100644
--- a/tests/start_mock_app.py
+++ b/tests/start_mock_app.py
@@ -8,27 +8,23 @@
 from scrapyd import Config
 from scrapyd.app import application
 
-
-def _get_config(args):
-    scrapyd_config = Config()
-    section = "scrapyd"
-    scrapyd_config.cp.set(section, "http_port", args.http_port)
-
-    if args.auth is not None:
-        username, password = args.auth.split(":")
-        scrapyd_config.cp.set(section, "username", username)
-        scrapyd_config.cp.set(section, "password", password)
-
-    return scrapyd_config
-
-
 if __name__ == "__main__":
     parser = argparse.ArgumentParser()
-    parser.add_argument("http_port", default=6800)
-    parser.add_argument("--auth", default=None)
+    parser.add_argument("http_port")
+    parser.add_argument("--username")
+    parser.add_argument("--password")
+
     args = parser.parse_args()
+
+    config = Config()
+    config.cp.set(Config.SECTION, "http_port", args.http_port)
+    if args.username and args.password:
+        config.cp.set(Config.SECTION, "username", args.username)
+        config.cp.set(Config.SECTION, "password", args.password)
+
     log.startLogging(sys.stdout)
-    conf = _get_config(args)
-    application = application(config=conf)
+
+    application = application(config=config)
     app.startApplication(application, save=False)
+
     reactor.run()
diff --git a/tests/test_eggstorage.py b/tests/test_eggstorage.py
index 86fa315c..cd6efeb8 100644
--- a/tests/test_eggstorage.py
+++ b/tests/test_eggstorage.py
@@ -44,6 +44,7 @@ def eggstorage(tmpdir):
     [
         (["zzz", "b", "ddd", "a", "x"], ["a", "b", "ddd", "x", "zzz"]),
         (["10", "1", "9"], ["1", "9", "10"]),
+        (["r10", "r1", "r9"], ["r1", "r10", "r9"]),
         (["2.11", "2.01", "2.9"], ["2.01", "2.9", "2.11"]),
     ],
 )
diff --git a/tests/test_endpoints.py b/tests/test_endpoints.py
index 8cbdeffb..d073c67c 100644
--- a/tests/test_endpoints.py
+++ b/tests/test_endpoints.py
@@ -34,7 +34,7 @@ def _deploy(mock_scrapyd, quotesbot_egg) -> Response:
 
 
 def test_urljoin(mock_scrapyd):
-    assert mock_scrapyd.urljoin("foo") == mock_scrapyd.url + "foo"
+    assert mock_scrapyd.urljoin("foo") == f"{mock_scrapyd.url}foo"
 
 
 def test_root(mock_scrapyd):
@@ -47,7 +47,7 @@ def test_root(mock_scrapyd):
 def test_auth():
     username, password = "Leonardo", "hunter2"
 
-    with MockScrapydServer(authentication=username + ":" + password) as server:
+    with MockScrapydServer(username=username, password=password) as server:
         assert requests.get(server.url).status_code == 401
 
         res = requests.get(server.url, auth=(username, password))