Harden Dataflow preview behavior

tests/test_service.py

@@ -24,7 +24,9 @@ from govoplan_dataflow.backend.service import (
     DataflowConflictError,
     DataflowNotFoundError,
     create_pipeline,
+    delete_pipeline,
     get_pipeline,
+    list_pipelines,
     preview_pipeline,
     update_pipeline,
 )
@@ -168,6 +170,37 @@ class DataflowServiceTests(unittest.TestCase):
                 pipeline_id=pipeline.id,
             )
 
+    def test_list_and_soft_delete_are_tenant_isolated(self) -> None:
+        first = self._create()
+        second = self._create(tenant_id="tenant-2")
+
+        self.assertEqual([first.id], [item.id for item in list_pipelines(self.session, tenant_id="tenant-1")])
+        self.assertEqual([second.id], [item.id for item in list_pipelines(self.session, tenant_id="tenant-2")])
+
+        delete_pipeline(
+            self.session,
+            tenant_id="tenant-1",
+            pipeline_id=first.id,
+            actor_id="user-2",
+        )
+        self.session.commit()
+
+        self.assertEqual([], list_pipelines(self.session, tenant_id="tenant-1"))
+        with self.assertRaises(DataflowNotFoundError):
+            get_pipeline(
+                self.session,
+                tenant_id="tenant-1",
+                pipeline_id=first.id,
+            )
+        self.assertEqual(
+            1,
+            self.session.scalar(
+                select(func.count())
+                .select_from(DataflowPipelineRevision)
+                .where(DataflowPipelineRevision.pipeline_id == first.id)
+            ),
+        )
+
     def test_saved_preview_records_lineage_but_not_result_rows(self) -> None:
         pipeline = self._create()