add tests and types for pipeline interface

src/delta_barth/pipelines.py

@@ -4,12 +4,15 @@ from datetime import datetime as Datetime
 
 from delta_barth.analysis import forecast
 from delta_barth.management import SESSION
+from delta_barth.types import JsonResponse, JsonStatus
 
 
 def pipeline_sales_forecast(
     company_id: int | None,
     start_date: Datetime | None,
-) -> str:
+) -> tuple[JsonResponse, JsonStatus]:
     result = forecast.pipeline(SESSION, company_id=company_id, start_date=start_date)
+    response = JsonResponse(result.response.model_dump_json())
+    status = JsonStatus(result.status.model_dump_json())
 
-    return result.model_dump_json()
+    return response, status

src/delta_barth/types.py

@@ -110,6 +110,10 @@ class PipeResult(t.Generic[R]):
         self.results = response
 
 
+JsonResponse = t.NewType("JsonResponse", str)
+JsonStatus = t.NewType("JsonStatus", str)
+
+
 # ** API
 class ApiCredentials(BaseModel):
     model_config: ConfigDict = ConfigDict(str_strip_whitespace=True)