feat: initialize governed datasources module

tests/test_tabular.py

@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import unittest
+
+from govoplan_core.core.datasources import DatasourceValidationError
+from govoplan_datasources.backend.tabular import (
+    fingerprint_rows,
+    infer_schema,
+    parse_csv_rows,
+)
+
+
+class DatasourceTabularTests(unittest.TestCase):
+    def test_csv_schema_and_fingerprint_are_stable(self) -> None:
+        rows = parse_csv_rows("id;name\n1;Ada\n2;\n", delimiter=";")
+        schema = infer_schema(rows)
+
+        self.assertEqual(["id", "name"], [field.name for field in schema])
+        self.assertTrue(schema[1].nullable)
+        self.assertEqual(
+            fingerprint_rows(rows, schema),
+            fingerprint_rows(rows, schema),
+        )
+
+    def test_csv_requires_headers(self) -> None:
+        with self.assertRaises(DatasourceValidationError):
+            parse_csv_rows("", delimiter=",")
+
+
+if __name__ == "__main__":
+    unittest.main()