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/parameters.py

@@ -30,12 +30,15 @@ class ParameterCreate(BaseModel):
             return None
         if normalized not in {"normal", "uniform", "triangular"}:
             raise ValueError(
-                "distribution_type must be normal, uniform, or triangular")
+                "distribution_type must be normal, uniform, or triangular"
+            )
         return normalized
 
     @field_validator("distribution_parameters")
     @classmethod
-    def empty_dict_to_none(cls, value: Optional[Dict[str, Any]]) -> Optional[Dict[str, Any]]:
+    def empty_dict_to_none(
+        cls, value: Optional[Dict[str, Any]]
+    ) -> Optional[Dict[str, Any]]:
         if value is None:
             return None
         return value or None
@@ -45,6 +48,7 @@ class ParameterRead(ParameterCreate):
     id: int
     model_config = ConfigDict(from_attributes=True)
 
+
 @router.post("/", response_model=ParameterRead)
 def create_parameter(param: ParameterCreate, db: Session = Depends(get_db)):
     scen = db.query(Scenario).filter(Scenario.id == param.scenario_id).first()
@@ -55,11 +59,15 @@ def create_parameter(param: ParameterCreate, db: Session = Depends(get_db)):
     distribution_parameters = param.distribution_parameters
 
     if distribution_id is not None:
-        distribution = db.query(Distribution).filter(
-            Distribution.id == distribution_id).first()
+        distribution = (
+            db.query(Distribution)
+            .filter(Distribution.id == distribution_id)
+            .first()
+        )
         if not distribution:
             raise HTTPException(
-                status_code=404, detail="Distribution not found")
+                status_code=404, detail="Distribution not found"
+            )
         distribution_type = distribution.distribution_type
         distribution_parameters = distribution.parameters or None