Add warning for empty extraction and update test join

Extractor now logs a warning if no dataframes are extracted. Updated test to use 's4h_join_data' instead of 'join_data' for merging filtered dataframes.

Author: dirreno

src/socio4health/extractor.py

@@ -180,6 +180,9 @@ def s4h_extract(self):
             logging.error(f"Exception while extracting data: {e}")
             raise ValueError(f"Extraction failed: {str(e)}")
 
+        if not self.dataframes:
+            logging.warning("No data was extracted. The extraction process returned an empty result.")
+
         return self.dataframes
 
     def _extract_online_mode(self):

tests/mytest.py

@@ -124,7 +124,7 @@ def test():
 
     """
     print('Horizontal merge___________________________________')
-    joined_df = har.join_data(filtered_ddfs)
+    joined_df = har.s4h_join_data(filtered_ddfs)
     available_cols = joined_df.columns.tolist()
 
     print(f"Available columns: {available_cols}")