wrap request validity check in function

cads_processing_api_service/costing.py

@@ -63,17 +63,11 @@ def estimate_cost(
             resource_id=process_id, table=table, session=catalogue_session
         )
     adaptor_properties = adaptors.get_adaptor_properties(dataset)
-    if not mandatory_inputs:
-        request_is_valid = False
-    else:
-        try:
-            adaptor = adaptors.instantiate_adaptor(
-                adaptor_properties=adaptor_properties
-            )
-            _ = adaptor.check_validity(request.get("inputs", {}))
-            request_is_valid = True
-        except cads_adaptors.exceptions.InvalidRequest:
-            request_is_valid = False
+    request_is_valid = check_request_validity(
+        request=request,
+        mandatory_inputs=mandatory_inputs,
+        adaptor_properties=adaptor_properties,
+    )
     costing_info = costing.compute_costing(
         request.get("inputs", {}), adaptor_properties, request_origin
     )
@@ -84,6 +78,36 @@ def estimate_cost(
     return cost
 
 
+def check_request_validity(
+    request: dict[str, Any], mandatory_inputs: bool, adaptor_properties: dict[str, Any]
+) -> bool:
+    """
+    Check if the request is valid.
+
+    Parameters
+    ----------
+    request : dict[str, Any]
+        Request to be processed.
+    mandatory_inputs : bool
+        Whether mandatory inputs have been provided.
+    adaptor_properties : dict[str, Any]
+        Adaptor properties.
+
+    Returns
+    -------
+    bool
+        Whether the request is valid.
+    """
+    if not mandatory_inputs:
+        return False
+    try:
+        adaptor = adaptors.instantiate_adaptor(adaptor_properties=adaptor_properties)
+        _ = adaptor.check_validity(request.get("inputs", {}))
+        return True
+    except cads_adaptors.exceptions.InvalidRequest:
+        return False
+
+
 def compute_highest_cost_limit_ratio(
     costing_info: models.CostingInfo,
 ) -> models.RequestCost: