Running single table report on multi table data (or vice versa) results in confusing error

sdmetrics/reports/base_report.py

@@ -53,6 +53,21 @@ def _validate_metadata_matches_data(self, real_data, synthetic_data, metadata):
             )
             raise ValueError(error_message)
 
+    def _validate_data_format(self, real_data, synthetic_data):
+        """Validate that the real and synthetic data are pd.DataFrame for single table reports."""
+        is_real_dataframe = isinstance(real_data, pd.DataFrame)
+        is_synthetic_dataframe = isinstance(synthetic_data, pd.DataFrame)
+        if is_real_dataframe and is_synthetic_dataframe:
+            return
+
+        error_message = (
+            f'Single table report {self.__class__.__name__} expects real and synthetic data to be'
+            ' pandas.DataFrame. If your real and synthetic data are dictionaries of tables, '
+            f'please use the multi-table {self.__class__.__name__} instead.'
+
+        )
+        raise ValueError(error_message)
+
     def _validate(self, real_data, synthetic_data, metadata):
         """Validate the inputs.
 
@@ -64,6 +79,7 @@ def _validate(self, real_data, synthetic_data, metadata):
             metadata (dict):
                 The metadata of the table.
         """
+        self._validate_data_format(real_data, synthetic_data)
         self._validate_metadata_matches_data(real_data, synthetic_data, metadata)
 
     def _handle_results(self, verbose):

sdmetrics/reports/multi_table/base_multi_table_report.py

@@ -1,4 +1,6 @@
 """Single table base property class."""
+import pandas as pd
+
 from sdmetrics.reports.base_report import BaseReport
 from sdmetrics.visualization import set_plotly_config
 
@@ -15,6 +17,28 @@ def __init__(self):
         super().__init__()
         self.table_names = []
 
+    def _validate_data_format(self, real_data, synthetic_data):
+        """Validate that the real and synthetic are dictionnaries of tables."""
+        is_real_dict = isinstance(real_data, dict)
+        is_synthetic_dict = isinstance(synthetic_data, dict)
+        if is_real_dict and is_synthetic_dict:
+            all_real_dataframes = all(
+                isinstance(table, pd.DataFrame) for table in real_data.values()
+            )
+            all_synthetic_dataframes = all(
+                isinstance(table, pd.DataFrame) for table in synthetic_data.values()
+            )
+            if all_real_dataframes and all_synthetic_dataframes:
+                return
+
+        error_message = (
+            f'Multi table report {self.__class__.__name__} expects real and synthetic data to be'
+            ' dictionaries of pandas.DataFrame. If your real and synthetic data are pd.DataFrame,'
+            f' please use the single-table {self.__class__.__name__} instead.'
+        )
+
+        raise ValueError(error_message)
+
     def _validate_relationships(self, real_data, synthetic_data, metadata):
         """Validate that the relationships are valid."""
         for rel in metadata.get('relationships', []):

tests/unit/reports/multi_table/test_base_multi_table_report.py

@@ -6,6 +6,7 @@
 import pandas as pd
 import pytest
 
+from sdmetrics.demos import load_demo
 from sdmetrics.reports.multi_table.base_multi_table_report import BaseMultiTableReport
 
 
@@ -22,6 +23,25 @@ def test__init__(self):
         assert report._properties == {}
         assert report.table_names == []
 
+    def test__validate_data_format(self):
+        """Test the ``_validate_data_format`` method.
+
+        This test checks that the method raises an error when the real and synthetic data are not
+        dictionnaries of pd.DataFrame.
+        """
+        # Setup
+        base_report = BaseMultiTableReport()
+        real_data, synthetic_data, _ = load_demo('single_table')
+
+        # Run and Assert
+        expected_message = (
+            'Multi table report BaseMultiTableReport expects real and synthetic data to be '
+            'dictionaries of pandas.DataFrame. If your real and synthetic data are '
+            'pd.DataFrame, please use the single-table BaseMultiTableReport instead.'
+        )
+        with pytest.raises(ValueError, match=expected_message):
+            base_report._validate_data_format(real_data, synthetic_data)
+
     def test__validate_relationships(self):
         """Test the ``_validate_relationships`` method."""
         # Setup

tests/unit/reports/test_base_report.py

@@ -7,10 +7,30 @@
 import pandas as pd
 import pytest
 
+from sdmetrics.demos import load_demo
 from sdmetrics.reports.base_report import BaseReport
 
 
 class TestBaseReport:
+    def test__validate_data_format(self):
+        """Test the ``_validate_data_format`` method.
+
+        This test checks that the method raises an error when the real and synthetic data are not
+        pandas.DataFrame.
+        """
+        # Setup
+        base_report = BaseReport()
+        real_data, synthetic_data, _ = load_demo('multi_table')
+
+        # Run and Assert
+        expected_message = (
+            'Single table report BaseReport expects real and synthetic data to be '
+            'pandas.DataFrame. If your real and synthetic data are dictionaries of '
+            'tables, please use the multi-table BaseReport instead.'
+        )
+        with pytest.raises(ValueError, match=expected_message):
+            base_report._validate_data_format(real_data, synthetic_data)
+
     def test__validate_metadata_matches_data(self):
         """Test the ``_validate_metadata_matches_data`` method.