Add validation for input path in select_table_schema method

Author: Sung Won Chung

data_diff/databases/duckdb.py

@@ -166,6 +166,10 @@ def create_connection(self):
     def select_table_schema(self, path: DbPath) -> str:
         database, schema, table = self._normalize_table_path(path)
 
+        # If path only contains one object, raise an error
+        if len(path) == 1:
+            raise ValueError('The input path needs to have more than one object in your data diff configuration.\nExpected format: database.schema.table or schema.table')
+
         info_schema_path = ["information_schema", "columns"]
 
         if database:
@@ -179,6 +183,7 @@ def select_table_schema(self, path: DbPath) -> str:
             f"WHERE table_name = '{table}' AND table_schema = '{schema}' and table_catalog = {dynamic_database_clause}"
         )
 
+
     def _normalize_table_path(self, path: DbPath) -> DbPath:
         if len(path) == 1:
             return None, self.default_schema, path[0]

tests/test_duckdb.py

@@ -12,7 +12,6 @@ def setUp(self):
         self.duckdb_conn = duckdb_differ.DuckDB(filepath=test_duckdb_filepath)
 
     def tearDown(self):
-        # Optional: delete file after tests
         os.remove(test_duckdb_filepath)
 
     def test_normalize_table_path(self):
@@ -29,9 +28,16 @@ def test_normalize_table_path(self):
             self.duckdb_conn._normalize_table_path(("test_database", "test_schema", "test_table", "extra"))
 
     def test_select_table_schema(self):
-        db_path = ("test_table",)
-        expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'main' and table_catalog = current_catalog()"
-        self.assertEqual(self.duckdb_conn.select_table_schema(db_path), expected_sql)
+        with self.assertRaises(ValueError) as context:
+            # Try to call the select_table_schema with only one value in the tuple
+            db_path = ("test_table",)
+            self.duckdb_conn.select_table_schema(db_path)
+
+        # Check that the message in the ValueError is what you expect
+        self.assertTrue(
+            "The input path needs to have more than one object in your data diff configuration.\nExpected format: database.schema.table or schema.table"
+            in str(context.exception)
+        )
 
         db_path = ("custom_schema", "test_table")
         expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'custom_schema' and table_catalog = current_catalog()"
@@ -40,7 +46,3 @@ def test_select_table_schema(self):
         db_path = ("custom_db", "custom_schema", "test_table")
         expected_sql = "SELECT column_name, data_type, datetime_precision, numeric_precision, numeric_scale FROM custom_db.information_schema.columns WHERE table_name = 'test_table' AND table_schema = 'custom_schema' and table_catalog = 'custom_db'"
         self.assertEqual(self.duckdb_conn.select_table_schema(db_path), expected_sql)
-
-
-if __name__ == "__main__":
-    unittest.main()