Refactor test cases for improved readability and consistency

- Updated test functions in various test files to enhance code clarity by formatting long lines and improving indentation.
- Adjusted assertions to use multi-line formatting for better readability.
- Added new test cases for theme settings API to ensure proper functionality.
- Ensured consistent use of line breaks and spacing across test files for uniformity.

routes/simulations.py

@@ -43,7 +43,9 @@ class SimulationRunResponse(BaseModel):
     summary: Dict[str, float | int]
 
 
-def _load_parameters(db: Session, scenario_id: int) -> List[SimulationParameterInput]:
+def _load_parameters(
+    db: Session, scenario_id: int
+) -> List[SimulationParameterInput]:
     db_params = (
         db.query(Parameter)
         .filter(Parameter.scenario_id == scenario_id)
@@ -60,17 +62,19 @@ def _load_parameters(db: Session, scenario_id: int) -> List[SimulationParameterI
 
 
 @router.post("/run", response_model=SimulationRunResponse)
-async def simulate(payload: SimulationRunRequest, db: Session = Depends(get_db)):
-    scenario = db.query(Scenario).filter(
-        Scenario.id == payload.scenario_id).first()
+async def simulate(
+    payload: SimulationRunRequest, db: Session = Depends(get_db)
+):
+    scenario = (
+        db.query(Scenario).filter(Scenario.id == payload.scenario_id).first()
+    )
     if scenario is None:
         raise HTTPException(
             status_code=status.HTTP_404_NOT_FOUND,
             detail="Scenario not found",
         )
 
-    parameters = payload.parameters or _load_parameters(
-        db, payload.scenario_id)
+    parameters = payload.parameters or _load_parameters(db, payload.scenario_id)
     if not parameters:
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,