Add stub methods (#2218)

sdv/multi_table/base.py

@@ -340,6 +340,10 @@ def _store_and_convert_original_cols(self, data):
             data[table] = dataframe
         return list_of_changed_tables
 
+    def _transform_helper(self, data):
+        """Stub method for transforming data patterns."""
+        return data
+
     def preprocess(self, data):
         """Transform the raw data to numerical space.
 
@@ -353,6 +357,7 @@ def preprocess(self, data):
         """
         list_of_changed_tables = self._store_and_convert_original_cols(data)
 
+        data = self._transform_helper(data)
         self.validate(data)
         if self._fitted:
             warnings.warn(
@@ -471,6 +476,10 @@ def reset_sampling(self):
     def _sample(self, scale):
         raise NotImplementedError()
 
+    def _reverse_transform_helper(self, sampled_data):
+        """Stub method for reverse transforming data patterns."""
+        return sampled_data
+
     def sample(self, scale=1.0):
         """Generate synthetic data for the entire dataset.
 
@@ -495,6 +504,7 @@ def sample(self, scale=1.0):
 
         with self._set_temp_numpy_seed(), disable_single_table_logger():
             sampled_data = self._sample(scale=scale)
+            sampled_data = self._reverse_transform_helper(sampled_data)
 
         total_rows = 0
         total_columns = 0

tests/unit/multi_table/test_base.py

@@ -763,6 +763,7 @@ def test_preprocess(self):
                 'id_upravna_enota': np.arange(10),
             }),
         }
+        instance._transform_helper = Mock(return_value=data)
 
         synth_nesreca = Mock()
         synth_oseba = Mock()
@@ -782,6 +783,7 @@ def test_preprocess(self):
             'oseba': synth_oseba._preprocess.return_value,
             'upravna_enota': synth_upravna_enota._preprocess.return_value,
         }
+        instance._transform_helper.assert_called_once_with(data)
         instance.validate.assert_called_once_with(data)
         assert instance.metadata._get_all_foreign_keys.call_args_list == [
             call('nesreca'),
@@ -1212,6 +1214,7 @@ def test_sample(self, mock_datetime, caplog):
             'table2': pd.DataFrame({'id': [1, 2, 3], 'name': ['John', 'Johanna', 'Doe']}),
         }
         instance._sample = Mock(return_value=data)
+        instance._reverse_transform_helper = Mock(return_value=data)
 
         synth_id = 'BaseMultiTableSynthesizer_1.0.0_92aff11e9a5649d1a280990d1231a5f5'
         instance._synthesizer_id = synth_id
@@ -1222,6 +1225,7 @@ def test_sample(self, mock_datetime, caplog):
 
         # Assert
         instance._sample.assert_called_once_with(scale=1.5)
+        instance._reverse_transform_helper.assert_called_once_with(data)
         assert caplog.messages[0] == str({
             'EVENT': 'Sample',
             'TIMESTAMP': '2024-04-19 16:20:10.037183',