diff --git a/tests/hpo/apps/main/conftest.py b/tests/hpo/apps/main/conftest.py
index 34d5a7c2..d961650a 100644
--- a/tests/hpo/apps/main/conftest.py
+++ b/tests/hpo/apps/main/conftest.py
@@ -12,8 +12,7 @@
 # Define type aliases for the database utility functions
 TrialCountFunc: TypeAlias = Callable[[Path, str], int]
 TrialValuesFunc: TypeAlias = Callable[[Path, str], list[float]]
-DBUtils: TypeAlias = dict[Literal["get_trial_count", "get_trial_values"],
-                         TrialCountFunc | TrialValuesFunc]
+DBUtils: TypeAlias = dict[Literal["get_trial_count", "get_trial_values"], TrialCountFunc | TrialValuesFunc]
 ConfigModFunc: TypeAlias = Callable[[Path, str, int, str], Path]
 
 
@@ -48,6 +47,7 @@ def temp_dir() -> Generator[Path, None, None]:
 @pytest.fixture
 def db_utils() -> DBUtils:
     """Fixture providing database utility functions"""
+
     def get_trial_count(db_path: Path, study_name: str) -> int:
         """Get the number of trials from the SQLite database for a specific study"""
         if not db_path.exists():
@@ -87,15 +87,13 @@ def get_trial_values(db_path: Path, study_name: str) -> list[float]:
         conn.close()
         return values
 
-    return {
-        "get_trial_count": get_trial_count,
-        "get_trial_values": get_trial_values
-    }
+    return {"get_trial_count": get_trial_count, "get_trial_values": get_trial_values}
 
 
 @pytest.fixture
 def config_modifier() -> ConfigModFunc:
     """Fixture providing configuration file modification functionality"""
+
     def modify_config(config_path: Path, study_name: str, n_trials: int, db_name: str) -> Path:
         """Modify config file with new study name and number of trials"""
         with open(config_path) as f:
diff --git a/tests/hpo/apps/main/test_optimize.py b/tests/hpo/apps/main/test_optimize.py
index 5b19a299..12b32ba6 100644
--- a/tests/hpo/apps/main/test_optimize.py
+++ b/tests/hpo/apps/main/test_optimize.py
@@ -5,11 +5,7 @@
 from conftest import ConfigModFunc, DBUtils
 
 
-def test_normal_execution(
-    temp_dir: Path,
-    db_utils: DBUtils,
-    config_modifier: ConfigModFunc
-) -> None:
+def test_normal_execution(temp_dir: Path, db_utils: DBUtils, config_modifier: ConfigModFunc) -> None:
     """Test normal execution without resume functionality"""
     from aiaccel.hpo.apps.optimize import main
 
diff --git a/tests/hpo/apps/main/test_resume.py b/tests/hpo/apps/main/test_resume.py
index 7551bc7b..44bfa82e 100644
--- a/tests/hpo/apps/main/test_resume.py
+++ b/tests/hpo/apps/main/test_resume.py
@@ -7,11 +7,7 @@
 from conftest import ConfigModFunc, DBUtils, TrialValuesFunc
 
 
-def test_optimization_consistency(
-    temp_dir: Path,
-    db_utils: DBUtils,
-    config_modifier: ConfigModFunc
-) -> None:
+def test_optimization_consistency(temp_dir: Path, db_utils: DBUtils, config_modifier: ConfigModFunc) -> None:
     """Test that split execution (resumable + resume) gives same results as normal execution."""
     from aiaccel.hpo.apps.optimize import main
 
@@ -59,11 +55,7 @@ def test_optimization_consistency(
     assert abs(normal_best - split_best) < 1e-6, f"Best values differ: normal={normal_best}, split={split_best}"
 
 
-def test_resumable_execution(
-    temp_dir: Path,
-    db_utils: DBUtils,
-    config_modifier: ConfigModFunc
-) -> None:
+def test_resumable_execution(temp_dir: Path, db_utils: DBUtils, config_modifier: ConfigModFunc) -> None:
     """Test execution with `--resumable`"""
     from aiaccel.hpo.apps.optimize import main
 
@@ -80,11 +72,7 @@ def test_resumable_execution(
     assert trial_count == 15
 
 
-def test_resume_execution(
-    temp_dir: Path,
-    db_utils: DBUtils,
-    config_modifier: ConfigModFunc
-) -> None:
+def test_resume_execution(temp_dir: Path, db_utils: DBUtils, config_modifier: ConfigModFunc) -> None:
     """Test the resume functionality of the optimization process."""
     from aiaccel.hpo.apps.optimize import main