diff --git a/radicale/tests/test_auth.py b/radicale/tests/test_auth.py
index 422f98c..9b136b3 100644
--- a/radicale/tests/test_auth.py
+++ b/radicale/tests/test_auth.py
@@ -40,13 +40,13 @@ class TestBaseAuthRequests(BaseTest):
     def setup(self):
         self.configuration = config.load()
         self.colpath = tempfile.mkdtemp()
-        self.configuration.set("storage", "filesystem_folder", self.colpath)
+        self.configuration["storage"]["filesystem_folder"] = self.colpath
         # Disable syncing to disk for better performance
-        self.configuration.set("storage", "filesystem_fsync", "False")
+        self.configuration["storage"]["filesystem_fsync"] = "False"
         # Required on Windows, doesn't matter on Unix
-        self.configuration.set("storage", "filesystem_close_lock_file", "True")
+        self.configuration["storage"]["filesystem_close_lock_file"] = "True"
         # Set incorrect authentication delay to a very low value
-        self.configuration.set("auth", "delay", "0.002")
+        self.configuration["auth"]["delay"] = "0.002"
 
     def teardown(self):
         shutil.rmtree(self.colpath)
@@ -56,10 +56,9 @@ class TestBaseAuthRequests(BaseTest):
         htpasswd_file_path = os.path.join(self.colpath, ".htpasswd")
         with open(htpasswd_file_path, "w") as f:
             f.write(htpasswd_content)
-        self.configuration.set("auth", "type", "htpasswd")
-        self.configuration.set("auth", "htpasswd_filename", htpasswd_file_path)
-        self.configuration.set("auth", "htpasswd_encryption",
-                               htpasswd_encryption)
+        self.configuration["auth"]["type"] = "htpasswd"
+        self.configuration["auth"]["htpasswd_filename"] = htpasswd_file_path
+        self.configuration["auth"]["htpasswd_encryption"] = htpasswd_encryption
         self.application = Application(self.configuration, self.logger)
         for user, password, expected_status in (
                 ("tmp", "bepo", 207), ("tmp", "tmp", 401), ("tmp", "", 401),
@@ -108,7 +107,7 @@ class TestBaseAuthRequests(BaseTest):
             "tmp:$2y$05$oD7hbiQFQlvCM7zoalo/T.MssV3VNTRI3w5KDnj8NTUKJNWfVpvRq")
 
     def test_remote_user(self):
-        self.configuration.set("auth", "type", "remote_user")
+        self.configuration["auth"]["type"] = "remote_user"
         self.application = Application(self.configuration, self.logger)
         status, _, answer = self.request(
             "PROPFIND", "/",
@@ -122,7 +121,7 @@ class TestBaseAuthRequests(BaseTest):
         assert ">/test/<" in answer
 
     def test_http_x_remote_user(self):
-        self.configuration.set("auth", "type", "http_x_remote_user")
+        self.configuration["auth"]["type"] = "http_x_remote_user"
         self.application = Application(self.configuration, self.logger)
         status, _, answer = self.request(
             "PROPFIND", "/",
@@ -137,7 +136,7 @@ class TestBaseAuthRequests(BaseTest):
 
     def test_custom(self):
         """Custom authentication."""
-        self.configuration.set("auth", "type", "tests.custom.auth")
+        self.configuration["auth"]["type"] = "tests.custom.auth"
         self.application = Application(self.configuration, self.logger)
         status, headers, answer = self.request(
             "PROPFIND", "/tmp", HTTP_AUTHORIZATION="Basic %s" %
diff --git a/radicale/tests/test_base.py b/radicale/tests/test_base.py
index 9ace4bf..773dc98 100644
--- a/radicale/tests/test_base.py
+++ b/radicale/tests/test_base.py
@@ -779,10 +779,10 @@ class BaseRequestsMixIn:
 
     def test_authentication(self):
         """Test if server sends authentication request."""
-        self.configuration.set("auth", "type", "htpasswd")
-        self.configuration.set("auth", "htpasswd_filename", os.devnull)
-        self.configuration.set("auth", "htpasswd_encryption", "plain")
-        self.configuration.set("rights", "type", "owner_only")
+        self.configuration["auth"]["type"] = "htpasswd"
+        self.configuration["auth"]["htpasswd_filename"] = os.devnull
+        self.configuration["auth"]["htpasswd_encryption"] = "plain"
+        self.configuration["rights"]["type"] = "owner_only"
         self.application = Application(self.configuration, self.logger)
         status, headers, answer = self.request("MKCOL", "/user/")
         assert status in (401, 403)
@@ -806,15 +806,14 @@ class BaseRequestsMixIn:
 
     def test_fsync(self):
         """Create a directory and file with syncing enabled."""
-        self.configuration.set("storage", "filesystem_fsync", "True")
+        self.configuration["storage"]["filesystem_fsync"] = "True"
         status, headers, answer = self.request("MKCALENDAR", "/calendar.ics/")
         assert status == 201
 
     def test_hook(self):
         """Run hook."""
-        self.configuration.set(
-            "storage", "hook", "mkdir %s" % os.path.join(
-                "collection-root", "created_by_hook"))
+        self.configuration["storage"]["hook"] = (
+            "mkdir %s" % os.path.join("collection-root", "created_by_hook"))
         status, headers, answer = self.request("MKCOL", "/calendar.ics/")
         assert status == 201
         status, headers, answer = self.request("PROPFIND", "/created_by_hook/")
@@ -822,9 +821,8 @@ class BaseRequestsMixIn:
 
     def test_hook_read_access(self):
         """Verify that hook is not run for read accesses."""
-        self.configuration.set(
-            "storage", "hook", "mkdir %s" % os.path.join(
-                "collection-root", "created_by_hook"))
+        self.configuration["storage"]["hook"] = (
+            "mkdir %s" % os.path.join("collection-root", "created_by_hook"))
         status, headers, answer = self.request("GET", "/")
         assert status == 303
         status, headers, answer = self.request("GET", "/created_by_hook/")
@@ -834,16 +832,15 @@ class BaseRequestsMixIn:
                         reason="flock command not found")
     def test_hook_storage_locked(self):
         """Verify that the storage is locked when the hook runs."""
-        self.configuration.set(
-            "storage", "hook", "flock -n .Radicale.lock || exit 0; exit 1")
+        self.configuration["storage"]["hook"] = (
+            "flock -n .Radicale.lock || exit 0; exit 1")
         status, headers, answer = self.request("MKCOL", "/calendar.ics/")
         assert status == 201
 
     def test_hook_principal_collection_creation(self):
         """Verify that the hooks runs when a new user is created."""
-        self.configuration.set(
-            "storage", "hook", "mkdir %s" % os.path.join(
-                "collection-root", "created_by_hook"))
+        self.configuration["storage"]["hook"] = (
+            "mkdir %s" % os.path.join("collection-root", "created_by_hook"))
         status, headers, answer = self.request("GET", "/", REMOTE_USER="user")
         assert status == 303
         status, headers, answer = self.request("PROPFIND", "/created_by_hook/")
@@ -851,7 +848,7 @@ class BaseRequestsMixIn:
 
     def test_hook_fail(self):
         """Verify that a request fails if the hook fails."""
-        self.configuration.set("storage", "hook", "exit 1")
+        self.configuration["storage"]["hook"] = "exit 1"
         try:
             status, headers, answer = self.request("MKCOL", "/calendar.ics/")
             assert status != 201
@@ -877,13 +874,13 @@ class BaseFileSystemTest(BaseTest):
 
     def setup(self):
         self.configuration = config.load()
-        self.configuration.set("storage", "type", self.storage_type)
+        self.configuration["storage"]["type"] = self.storage_type
         self.colpath = tempfile.mkdtemp()
-        self.configuration.set("storage", "filesystem_folder", self.colpath)
+        self.configuration["storage"]["filesystem_folder"] = self.colpath
         # Disable syncing to disk for better performance
-        self.configuration.set("storage", "filesystem_fsync", "False")
+        self.configuration["storage"]["filesystem_fsync"] = "False"
         # Required on Windows, doesn't matter on Unix
-        self.configuration.set("storage", "filesystem_close_lock_file", "True")
+        self.configuration["storage"]["filesystem_close_lock_file"] = "True"
         self.application = Application(self.configuration, self.logger)
 
     def teardown(self):
diff --git a/radicale/tests/test_rights.py b/radicale/tests/test_rights.py
index 0bdaf57..36c2833 100644
--- a/radicale/tests/test_rights.py
+++ b/radicale/tests/test_rights.py
@@ -34,11 +34,11 @@ class TestBaseAuthRequests(BaseTest):
     def setup(self):
         self.configuration = config.load()
         self.colpath = tempfile.mkdtemp()
-        self.configuration.set("storage", "filesystem_folder", self.colpath)
+        self.configuration["storage"]["filesystem_folder"] = self.colpath
         # Disable syncing to disk for better performance
-        self.configuration.set("storage", "filesystem_fsync", "False")
+        self.configuration["storage"]["filesystem_fsync"] = "False"
         # Required on Windows, doesn't matter on Unix
-        self.configuration.set("storage", "filesystem_close_lock_file", "True")
+        self.configuration["storage"]["filesystem_close_lock_file"] = "True"
 
     def teardown(self):
         shutil.rmtree(self.colpath)
@@ -49,10 +49,10 @@ class TestBaseAuthRequests(BaseTest):
         htpasswd_file_path = os.path.join(self.colpath, ".htpasswd")
         with open(htpasswd_file_path, "w") as f:
             f.write("tmp:bepo\nother:bepo")
-        self.configuration.set("rights", "type", rights_type)
-        self.configuration.set("auth", "type", "htpasswd")
-        self.configuration.set("auth", "htpasswd_filename", htpasswd_file_path)
-        self.configuration.set("auth", "htpasswd_encryption", "plain")
+        self.configuration["rights"]["type"] = rights_type
+        self.configuration["auth"]["type"] = "htpasswd"
+        self.configuration["auth"]["htpasswd_filename"] = htpasswd_file_path
+        self.configuration["auth"]["htpasswd_encryption"] = "plain"
         self.application = Application(self.configuration, self.logger)
         for u in ("tmp", "other"):
             status, _, _ = self.request(
@@ -125,7 +125,7 @@ permission: rw
 user: .*
 collection: custom(/.*)?
 permission: r""")
-        self.configuration.set("rights", "file", rights_file_path)
+        self.configuration["rights"]["file"] = rights_file_path
         self._test_rights("from_file", "", "/other", "r", 401)
         self._test_rights("from_file", "tmp", "/other", "r", 403)
         self._test_rights("from_file", "", "/custom/sub", "r", 404)