diff --git a/tox.ini b/tox.ini
index f9776382db0770e3efe1b2711f50bb5b3adde1ec..94c2dc8affb280d3e7f6cff4536636432c9f7749 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py36, py37, py38
+envlist=py36, py37, py38, py39
 skip_missing_interpreters = true
 
 [testenv]
diff --git a/unittests/test_authentication_plain.py b/unittests/test_authentication_plain.py
index 26c57e953f28a2a0ab80e35026c27ff74f18d370..1b7cbf0cd9a61b6ddadf54f908b25a82d87efa42 100644
--- a/unittests/test_authentication_plain.py
+++ b/unittests/test_authentication_plain.py
@@ -27,8 +27,9 @@ Unit tests for the modul caosdb.connection.authentication.plain.
 """
 
 from __future__ import unicode_literals
-from pytest import raises
+
 from caosdb.connection.authentication.plain import PlainTextCredentialsProvider
+from pytest import raises
 
 
 def test_subclass_configure():
@@ -51,8 +52,8 @@ def test_subclass_configure():
 
     with raises(TypeError) as exc_info:
         instance.configure(password="OH NO!")
-    assert exc_info.value.args[0] == ("configure() got multiple values for "
-                                      "keyword argument 'password'")
+    assert exc_info.value.args[0].endswith("configure() got multiple values for "
+                                           "keyword argument 'password'")
 
 
 def test_plain_has_logger():
diff --git a/unittests/test_connection.py b/unittests/test_connection.py
index 5c1518c65b51087ace514ca26fa77eff53130c73..60f1b73584f06f3e691ecbf52303906366e96fc0 100644
--- a/unittests/test_connection.py
+++ b/unittests/test_connection.py
@@ -23,23 +23,27 @@
 #
 """Test caosdb.connection."""
 # pylint: disable=missing-docstring
-from __future__ import unicode_literals, print_function
-from builtins import bytes, str  # pylint: disable=redefined-builtin
+from __future__ import print_function, unicode_literals
+
 import re
-from pytest import raises
-from nose.tools import (assert_equal as eq, assert_raises as raiz, assert_true
-                        as tru, assert_is_not_none as there, assert_false as
-                        falz)
-from caosdb.exceptions import ConfigurationException, LoginFailedException
-from caosdb.connection.utils import urlencode, make_uri_path, quote
-from caosdb.connection.connection import (
-    configure_connection, CaosDBServerConnection,
-    _DefaultCaosDBServerConnection)
-from caosdb.connection.mockup import (MockUpServerConnection, MockUpResponse,
-                                      _request_log_message)
-from caosdb.configuration import get_config, _reset_config
-from caosdb.connection.authentication.interface import CredentialsAuthenticator
+from builtins import bytes, str  # pylint: disable=redefined-builtin
+
 from caosdb import execute_query
+from caosdb.configuration import _reset_config, get_config
+from caosdb.connection.authentication.interface import CredentialsAuthenticator
+from caosdb.connection.connection import (CaosDBServerConnection,
+                                          _DefaultCaosDBServerConnection,
+                                          configure_connection)
+from caosdb.connection.mockup import (MockUpResponse, MockUpServerConnection,
+                                      _request_log_message)
+from caosdb.connection.utils import make_uri_path, quote, urlencode
+from caosdb.exceptions import ConfigurationException, LoginFailedException
+from nose.tools import assert_equal as eq
+from nose.tools import assert_false as falz
+from nose.tools import assert_is_not_none as there
+from nose.tools import assert_raises as raiz
+from nose.tools import assert_true as tru
+from pytest import raises
 
 
 def setup_module():
@@ -96,6 +100,7 @@ def test_configure_connection():
         get_config().add_section("Connection")
     get_config().set("Connection", "url", "https://host.de")
     get_config().set("Connection", "username", "test_username")
+    get_config().set("Connection", "password_method", "plain")
     get_config().set("Connection", "password", "test_password")
     get_config().set("Connection", "timeout", "200")
 
diff --git a/unittests/test_entity.py b/unittests/test_entity.py
index d877e1ab7267977a7e73d65033d6f02c16ea5521..e98dfbef5b6b5e5f691e8aecc2fa7d4a86991452 100644
--- a/unittests/test_entity.py
+++ b/unittests/test_entity.py
@@ -35,6 +35,7 @@ class TestEntity(unittest.TestCase):
     def setUp(self):
         self.assertIsNotNone(Entity)
         configure_connection(url="unittests", username="testuser",
+                             password_method="plain",
                              password="testpassword", timeout=200,
                              implementation=MockUpServerConnection)
 
diff --git a/unittests/test_file.py b/unittests/test_file.py
index 957c578062b25c74547b599a25802938b057a2e0..3c80af7f362a7cdabe0a9ebc89cd2986d04fe242 100644
--- a/unittests/test_file.py
+++ b/unittests/test_file.py
@@ -22,16 +22,18 @@
 # ** end header
 #
 """Tests for the File class."""
-# pylint: disable=missing-docstring
-from nose.tools import (assert_is_not_none as there, assert_true as tru,
-                        assert_equal as eq)
-from caosdb import Record, File, configure_connection
+from caosdb import File, Record, configure_connection
 from caosdb.connection.mockup import MockUpServerConnection
+# pylint: disable=missing-docstring
+from nose.tools import assert_equal as eq
+from nose.tools import assert_is_not_none as there
+from nose.tools import assert_true as tru
 
 
 def setup_module():
     there(File)
     configure_connection(url="unittests", username="testuser",
+                         password_method="plain",
                          password="testpassword", timeout=200,
                          implementation=MockUpServerConnection)
 
diff --git a/unittests/test_record_type.py b/unittests/test_record_type.py
index c105220c53579537994648b2f9bae5b4d378be13..f31c56decfc394211940296babc83200a470cc8a 100644
--- a/unittests/test_record_type.py
+++ b/unittests/test_record_type.py
@@ -22,16 +22,18 @@
 # ** end header
 #
 """Tests for the RecordType class."""
-# pylint: disable=missing-docstring
-from nose.tools import (assert_is_not_none as there, assert_true as tru,
-                        assert_equal as eq)
 from caosdb import Entity, RecordType, configure_connection
 from caosdb.connection.mockup import MockUpServerConnection
+# pylint: disable=missing-docstring
+from nose.tools import assert_equal as eq
+from nose.tools import assert_is_not_none as there
+from nose.tools import assert_true as tru
 
 
 def setup_module():
     there(RecordType)
     configure_connection(url="unittests", username="testuser",
+                         password_method="plain",
                          password="testpassword", timeout=200,
                          implementation=MockUpServerConnection)