diff --git a/openml/cli.py b/openml/cli.py
index 0afb089c2..18192a7db 100644
--- a/openml/cli.py
+++ b/openml/cli.py
@@ -109,7 +109,7 @@ def check_server(server: str) -> str:
 
     def replace_shorthand(server: str) -> str:
         if server == "test":
-            return "https://test.openml.org/api/v1/xml"
+            return f"{config.TEST_SERVER_URL}/api/v1/xml"
         if server == "production":
             return "https://www.openml.org/api/v1/xml"
         return server
diff --git a/openml/config.py b/openml/config.py
index e6104fd7f..5b2d69067 100644
--- a/openml/config.py
+++ b/openml/config.py
@@ -27,6 +27,8 @@
 OPENML_SKIP_PARQUET_ENV_VAR = "OPENML_SKIP_PARQUET"
 _TEST_SERVER_NORMAL_USER_KEY = "normaluser"
 
+TEST_SERVER_URL = "https://test.openml.org"
+
 
 class _Config(TypedDict):
     apikey: str
@@ -213,7 +215,7 @@ class ConfigurationForExamples:
     _last_used_server = None
     _last_used_key = None
     _start_last_called = False
-    _test_server = "https://test.openml.org/api/v1/xml"
+    _test_server = f"{TEST_SERVER_URL}/api/v1/xml"
     _test_apikey = _TEST_SERVER_NORMAL_USER_KEY
 
     @classmethod
diff --git a/openml/tasks/functions.py b/openml/tasks/functions.py
index 3df2861c0..2bf1a40f4 100644
--- a/openml/tasks/functions.py
+++ b/openml/tasks/functions.py
@@ -415,9 +415,10 @@ def get_task(
     if not isinstance(task_id, int):
         raise TypeError(f"Task id should be integer, is {type(task_id)}")
 
-    cache_key_dir = openml.utils._create_cache_directory_for_id(TASKS_CACHE_DIR_NAME, task_id)
-    tid_cache_dir = cache_key_dir / str(task_id)
-    tid_cache_dir_existed = tid_cache_dir.exists()
+    task_cache_directory = openml.utils._create_cache_directory_for_id(
+        TASKS_CACHE_DIR_NAME, task_id
+    )
+    task_cache_directory_existed = task_cache_directory.exists()
     try:
         task = _get_task_description(task_id)
         dataset = get_dataset(task.dataset_id, **get_dataset_kwargs)
@@ -431,8 +432,8 @@ def get_task(
         if download_splits and isinstance(task, OpenMLSupervisedTask):
             task.download_split()
     except Exception as e:
-        if not tid_cache_dir_existed:
-            openml.utils._remove_cache_dir_for_id(TASKS_CACHE_DIR_NAME, tid_cache_dir)
+        if not task_cache_directory_existed:
+            openml.utils._remove_cache_dir_for_id(TASKS_CACHE_DIR_NAME, task_cache_directory)
         raise e
 
     return task
diff --git a/openml/testing.py b/openml/testing.py
index 8d3bbbd5b..9ee555a91 100644
--- a/openml/testing.py
+++ b/openml/testing.py
@@ -47,7 +47,7 @@ class TestBase(unittest.TestCase):
         "user": [],
     }
     flow_name_tracker: ClassVar[list[str]] = []
-    test_server = "https://test.openml.org/api/v1/xml"
+    test_server = f"{openml.config.TEST_SERVER_URL}/api/v1/xml"
     admin_key = "abc"
     user_key = openml.config._TEST_SERVER_NORMAL_USER_KEY
 
diff --git a/tests/conftest.py b/tests/conftest.py
index bd974f3f3..29366ce37 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -277,7 +277,7 @@ def with_server(request):
         openml.config.apikey = None
         yield
         return
-    openml.config.server = "https://test.openml.org/api/v1/xml"
+    openml.config.server = f"{openml.config.TEST_SERVER_URL}/api/v1/xml"
     openml.config.apikey = TestBase.user_key
     yield
 
diff --git a/tests/files/localhost:8080 b/tests/files/localhost:8080
new file mode 120000
index 000000000..334c709ef
--- /dev/null
+++ b/tests/files/localhost:8080
@@ -0,0 +1 @@
+org/openml/test
\ No newline at end of file
diff --git a/tests/test_datasets/test_dataset_functions.py b/tests/test_datasets/test_dataset_functions.py
index c41664ba7..d8a9d80b9 100644
--- a/tests/test_datasets/test_dataset_functions.py
+++ b/tests/test_datasets/test_dataset_functions.py
@@ -527,19 +527,12 @@ def test_deletion_of_cache_dir(self):
     def test_deletion_of_cache_dir_faulty_download(self, patch):
         patch.side_effect = Exception("Boom!")
         self.assertRaisesRegex(Exception, "Boom!", openml.datasets.get_dataset, dataset_id=1)
-        datasets_cache_dir = os.path.join(self.workdir, "org", "openml", "test", "datasets")
+        datasets_cache_dir = os.path.join(openml.config.get_cache_directory(), "datasets")
         assert len(os.listdir(datasets_cache_dir)) == 0
 
     @pytest.mark.uses_test_server()
     def test_publish_dataset(self):
-        # lazy loading not possible as we need the arff-file.
-        openml.datasets.get_dataset(3, download_data=True)
-        file_path = os.path.join(
-            openml.config.get_cache_directory(),
-            "datasets",
-            "3",
-            "dataset.arff",
-        )
+        arff_file_path = self.static_cache_dir / "org" / "openml" / "test" / "datasets" / "2" / "dataset.arff"
         dataset = OpenMLDataset(
             "anneal",
             "test",
@@ -547,7 +540,7 @@ def test_publish_dataset(self):
             version=1,
             licence="public",
             default_target_attribute="class",
-            data_file=file_path,
+            data_file=arff_file_path,
         )
         dataset.publish()
         TestBase._mark_entity_for_removal("data", dataset.dataset_id)
@@ -886,7 +879,7 @@ def test_create_invalid_dataset(self):
 
     @pytest.mark.uses_test_server()
     def test_get_online_dataset_arff(self):
-        dataset_id = 100  # Australian
+        dataset_id = 128  # iris -- one of the few datasets without parquet file
         # lazy loading not used as arff file is checked.
         dataset = openml.datasets.get_dataset(dataset_id, download_data=True)
         decoder = arff.ArffDecoder()
@@ -1464,8 +1457,9 @@ def test_data_edit_critical_field(self):
                     raise e
                 time.sleep(10)
                 # Delete the cache dir to get the newer version of the dataset
+                
                 shutil.rmtree(
-                    os.path.join(self.workdir, "org", "openml", "test", "datasets", str(did)),
+                    os.path.join(openml.config.get_cache_directory(), "datasets", str(did)),
                 )
 
     @pytest.mark.uses_test_server()
@@ -1730,7 +1724,6 @@ def test_delete_dataset(self):
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_dataset_not_owned(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = (
         test_files_directory / "mock_responses" / "datasets" / "data_delete_not_owned.xml"
     )
@@ -1745,14 +1738,13 @@ def test_delete_dataset_not_owned(mock_delete, test_files_directory, test_api_ke
     ):
         openml.datasets.delete_dataset(40_000)
 
-    dataset_url = "https://test.openml.org/api/v1/xml/data/40000"
+    dataset_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/data/40000"
     assert dataset_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_dataset_with_run(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = (
         test_files_directory / "mock_responses" / "datasets" / "data_delete_has_tasks.xml"
     )
@@ -1767,14 +1759,13 @@ def test_delete_dataset_with_run(mock_delete, test_files_directory, test_api_key
     ):
         openml.datasets.delete_dataset(40_000)
 
-    dataset_url = "https://test.openml.org/api/v1/xml/data/40000"
+    dataset_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/data/40000"
     assert dataset_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_dataset_success(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = (
         test_files_directory / "mock_responses" / "datasets" / "data_delete_successful.xml"
     )
@@ -1786,14 +1777,13 @@ def test_delete_dataset_success(mock_delete, test_files_directory, test_api_key)
     success = openml.datasets.delete_dataset(40000)
     assert success
 
-    dataset_url = "https://test.openml.org/api/v1/xml/data/40000"
+    dataset_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/data/40000"
     assert dataset_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_unknown_dataset(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = (
         test_files_directory / "mock_responses" / "datasets" / "data_delete_not_exist.xml"
     )
@@ -1808,7 +1798,7 @@ def test_delete_unknown_dataset(mock_delete, test_files_directory, test_api_key)
     ):
         openml.datasets.delete_dataset(9_999_999)
 
-    dataset_url = "https://test.openml.org/api/v1/xml/data/9999999"
+    dataset_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/data/9999999"
     assert dataset_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
@@ -1903,9 +1893,8 @@ def _dataset_features_is_downloaded(did: int):
 
 
 def _dataset_data_file_is_downloaded(did: int):
-    parquet_present = _dataset_file_is_downloaded(did, "dataset.pq")
-    arff_present = _dataset_file_is_downloaded(did, "dataset.arff")
-    return parquet_present or arff_present
+    cache_directory = Path(openml.config.get_cache_directory()) / "datasets" / str(did)
+    return any(f.suffix in (".pq", ".arff") for f in cache_directory.iterdir())
 
 
 def _assert_datasets_retrieved_successfully(
@@ -2010,7 +1999,7 @@ def test_get_dataset_parquet(requests_mock, test_files_directory):
             test_files_directory / "mock_responses" / "datasets" / "data_description_61.xml"
     )
     # While the mocked example is from production, unit tests by default connect to the test server.
-    requests_mock.get("https://test.openml.org/api/v1/xml/data/61", text=content_file.read_text())
+    requests_mock.get(f"{openml.config.TEST_SERVER_URL}/api/v1/xml/data/61", text=content_file.read_text())
     dataset = openml.datasets.get_dataset(61, download_data=True)
     assert dataset._parquet_url is not None
     assert dataset.parquet_file is not None
diff --git a/tests/test_flows/test_flow_functions.py b/tests/test_flows/test_flow_functions.py
index 2339b27c8..790686d94 100644
--- a/tests/test_flows/test_flow_functions.py
+++ b/tests/test_flows/test_flow_functions.py
@@ -453,7 +453,6 @@ def test_delete_flow(self):
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_flow_not_owned(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "flows" / "flow_delete_not_owned.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -466,14 +465,13 @@ def test_delete_flow_not_owned(mock_delete, test_files_directory, test_api_key):
     ):
         openml.flows.delete_flow(40_000)
 
-    flow_url = "https://test.openml.org/api/v1/xml/flow/40000"
+    flow_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/flow/40000"
     assert flow_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_flow_with_run(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "flows" / "flow_delete_has_runs.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -486,14 +484,13 @@ def test_delete_flow_with_run(mock_delete, test_files_directory, test_api_key):
     ):
         openml.flows.delete_flow(40_000)
 
-    flow_url = "https://test.openml.org/api/v1/xml/flow/40000"
+    flow_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/flow/40000"
     assert flow_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_subflow(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "flows" / "flow_delete_is_subflow.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -506,14 +503,13 @@ def test_delete_subflow(mock_delete, test_files_directory, test_api_key):
     ):
         openml.flows.delete_flow(40_000)
 
-    flow_url = "https://test.openml.org/api/v1/xml/flow/40000"
+    flow_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/flow/40000"
     assert flow_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_flow_success(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "flows" / "flow_delete_successful.xml"
     mock_delete.return_value = create_request_response(
         status_code=200,
@@ -523,7 +519,7 @@ def test_delete_flow_success(mock_delete, test_files_directory, test_api_key):
     success = openml.flows.delete_flow(33364)
     assert success
 
-    flow_url = "https://test.openml.org/api/v1/xml/flow/33364"
+    flow_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/flow/33364"
     assert flow_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
@@ -531,7 +527,6 @@ def test_delete_flow_success(mock_delete, test_files_directory, test_api_key):
 @mock.patch.object(requests.Session, "delete")
 @pytest.mark.xfail(reason="failures_issue_1544", strict=False)
 def test_delete_unknown_flow(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "flows" / "flow_delete_not_exist.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -544,6 +539,6 @@ def test_delete_unknown_flow(mock_delete, test_files_directory, test_api_key):
     ):
         openml.flows.delete_flow(9_999_999)
 
-    flow_url = "https://test.openml.org/api/v1/xml/flow/9999999"
+    flow_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/flow/9999999"
     assert flow_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
diff --git a/tests/test_openml/test_config.py b/tests/test_openml/test_config.py
index 7ef223504..3ff7bd55e 100644
--- a/tests/test_openml/test_config.py
+++ b/tests/test_openml/test_config.py
@@ -78,7 +78,7 @@ def test_get_config_as_dict(self):
         config = openml.config.get_config_as_dict()
         _config = {}
         _config["apikey"] = TestBase.user_key
-        _config["server"] = "https://test.openml.org/api/v1/xml"
+        _config["server"] = f"{openml.config.TEST_SERVER_URL}/api/v1/xml"
         _config["cachedir"] = self.workdir
         _config["avoid_duplicate_runs"] = False
         _config["connection_n_retries"] = 20
diff --git a/tests/test_runs/test_run_functions.py b/tests/test_runs/test_run_functions.py
index 8f2c505b7..dda940e4d 100644
--- a/tests/test_runs/test_run_functions.py
+++ b/tests/test_runs/test_run_functions.py
@@ -1813,7 +1813,6 @@ def test_initialize_model_from_run_nonstrict(self):
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_run_not_owned(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "runs" / "run_delete_not_owned.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -1826,14 +1825,13 @@ def test_delete_run_not_owned(mock_delete, test_files_directory, test_api_key):
     ):
         openml.runs.delete_run(40_000)
 
-    run_url = "https://test.openml.org/api/v1/xml/run/40000"
+    run_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/run/40000"
     assert run_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_run_success(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "runs" / "run_delete_successful.xml"
     mock_delete.return_value = create_request_response(
         status_code=200,
@@ -1843,14 +1841,13 @@ def test_delete_run_success(mock_delete, test_files_directory, test_api_key):
     success = openml.runs.delete_run(10591880)
     assert success
 
-    run_url = "https://test.openml.org/api/v1/xml/run/10591880"
+    run_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/run/10591880"
     assert run_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_unknown_run(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "runs" / "run_delete_not_exist.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -1863,7 +1860,7 @@ def test_delete_unknown_run(mock_delete, test_files_directory, test_api_key):
     ):
         openml.runs.delete_run(9_999_999)
 
-    run_url = "https://test.openml.org/api/v1/xml/run/9999999"
+    run_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/run/9999999"
     assert run_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
@@ -1873,6 +1870,10 @@ def test_delete_unknown_run(mock_delete, test_files_directory, test_api_key):
     Version(sklearn.__version__) < Version("0.21"),
     reason="couldn't perform local tests successfully w/o bloating RAM",
     )
+@unittest.skipIf(
+    Version(sklearn.__version__) >= Version("1.8"),
+    reason="predictions differ significantly",
+    )
 @mock.patch("openml_sklearn.SklearnExtension._prevent_optimize_n_jobs")
 @pytest.mark.uses_test_server()
 def test__run_task_get_arffcontent_2(parallel_mock):
diff --git a/tests/test_tasks/test_task_functions.py b/tests/test_tasks/test_task_functions.py
index d44717177..6951bf36f 100644
--- a/tests/test_tasks/test_task_functions.py
+++ b/tests/test_tasks/test_task_functions.py
@@ -96,7 +96,9 @@ def test_list_tasks_empty(self):
 
     @pytest.mark.uses_test_server()
     def test_list_tasks_by_tag(self):
-        num_basic_tasks = 100  # number is flexible, check server if fails
+        # Server starts with 99 active tasks with the tag, and one 'in_preparation',
+        # so depending on the processing of the last dataset, there may be 99 or 100 matches.
+        num_basic_tasks = 99
         tasks = openml.tasks.list_tasks(tag="OpenML100")
         assert len(tasks) >= num_basic_tasks
         for task in tasks.to_dict(orient="index").values():
@@ -156,13 +158,13 @@ def test_get_task(self):
         task = openml.tasks.get_task(1, download_data=True)  # anneal; crossvalidation
         assert isinstance(task, OpenMLTask)
         assert os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "1", "task.xml")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "1", "task.xml")
         )
         assert not os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "1", "datasplits.arff")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "1", "datasplits.arff")
         )
         assert os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "datasets", "1", "dataset.arff")
+            os.path.join(openml.config.get_cache_directory(), "datasets", "1", "dataset_1.pq")
         )
 
     @pytest.mark.uses_test_server()
@@ -170,21 +172,21 @@ def test_get_task_lazy(self):
         task = openml.tasks.get_task(2, download_data=False)  # anneal; crossvalidation
         assert isinstance(task, OpenMLTask)
         assert os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "2", "task.xml")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "2", "task.xml")
         )
         assert task.class_labels == ["1", "2", "3", "4", "5", "U"]
 
         assert not os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "2", "datasplits.arff")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "2", "datasplits.arff")
         )
         # Since the download_data=False is propagated to get_dataset
         assert not os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "datasets", "2", "dataset.arff")
+            os.path.join(openml.config.get_cache_directory(), "datasets", "2", "dataset.arff")
         )
 
         task.download_split()
         assert os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "2", "datasplits.arff")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "2", "datasplits.arff")
         )
 
     @mock.patch("openml.tasks.functions.get_dataset")
@@ -228,7 +230,7 @@ def test_download_split(self):
         split = task.download_split()
         assert type(split) == OpenMLSplit
         assert os.path.exists(
-            os.path.join(self.workdir, "org", "openml", "test", "tasks", "1", "datasplits.arff")
+            os.path.join(openml.config.get_cache_directory(), "tasks", "1", "datasplits.arff")
         )
 
     def test_deletion_of_cache_dir(self):
@@ -244,7 +246,6 @@ def test_deletion_of_cache_dir(self):
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_task_not_owned(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "tasks" / "task_delete_not_owned.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -257,14 +258,13 @@ def test_delete_task_not_owned(mock_delete, test_files_directory, test_api_key):
     ):
         openml.tasks.delete_task(1)
 
-    task_url = "https://test.openml.org/api/v1/xml/task/1"
+    task_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/task/1"
     assert task_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_task_with_run(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "tasks" / "task_delete_has_runs.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -277,14 +277,13 @@ def test_delete_task_with_run(mock_delete, test_files_directory, test_api_key):
     ):
         openml.tasks.delete_task(3496)
 
-    task_url = "https://test.openml.org/api/v1/xml/task/3496"
+    task_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/task/3496"
     assert task_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_success(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "tasks" / "task_delete_successful.xml"
     mock_delete.return_value = create_request_response(
         status_code=200,
@@ -294,14 +293,13 @@ def test_delete_success(mock_delete, test_files_directory, test_api_key):
     success = openml.tasks.delete_task(361323)
     assert success
 
-    task_url = "https://test.openml.org/api/v1/xml/task/361323"
+    task_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/task/361323"
     assert task_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")
 
 
 @mock.patch.object(requests.Session, "delete")
 def test_delete_unknown_task(mock_delete, test_files_directory, test_api_key):
-    openml.config.start_using_configuration_for_example()
     content_file = test_files_directory / "mock_responses" / "tasks" / "task_delete_not_exist.xml"
     mock_delete.return_value = create_request_response(
         status_code=412,
@@ -314,6 +312,6 @@ def test_delete_unknown_task(mock_delete, test_files_directory, test_api_key):
     ):
         openml.tasks.delete_task(9_999_999)
 
-    task_url = "https://test.openml.org/api/v1/xml/task/9999999"
+    task_url = f"{openml.config.TEST_SERVER_URL}/api/v1/xml/task/9999999"
     assert task_url == mock_delete.call_args.args[0]
     assert test_api_key == mock_delete.call_args.kwargs.get("params", {}).get("api_key")