lineage helper api

tests/core/test_lineage_state.py

@@ -10,6 +10,15 @@ from wf_core import (
     StateSchema,
     Workflow,
 )
+from wf_core.models.reducers import ReducerRef
+from wf_core.paths import StatePath
+from wf_core.run_state import StateWrite
+from wf_core.runtime.lineage import (
+    add_lineage,
+    append_lineage_writes,
+    lineage_patch,
+    lineage_state_view,
+)
 from wf_core.runtime.ops.runs import create_run_state
 
 
@@ -31,6 +40,55 @@ def test_create_run_state_initializes_root_scope_and_lineage() -> None:
     assert run.frames["root"].parent_lineage_id is None
 
 
+def test_add_lineage_rejects_duplicate_or_unknown_scope() -> None:
+    run = create_run_state(_minimal_workflow(), {"value": "seed"})
+
+    add_lineage(run, scope_id="root", lineage_id="child", parent_id="root")
+
+    assert run.lineages["child"].scope_id == "root"
+    assert run.lineages["child"].parent_id == "root"
+
+    try:
+        add_lineage(run, scope_id="root", lineage_id="child", parent_id="root")
+    except ValueError as exc:
+        assert "duplicate lineage" in str(exc)
+    else:
+        raise AssertionError("expected duplicate lineage error")
+
+    try:
+        add_lineage(run, scope_id="missing", lineage_id="other", parent_id="root")
+    except ValueError as exc:
+        assert "unknown scope" in str(exc)
+    else:
+        raise AssertionError("expected unknown scope error")
+
+
+def test_lineage_helpers_store_ordered_writes_and_preserve_replay_values() -> None:
+    run = create_run_state(_minimal_workflow(), {"value": "seed"})
+    add_lineage(run, scope_id="root", lineage_id="child", parent_id="root")
+    writes = [
+        StateWrite(
+            path=StatePath(("value",)),
+            incoming_value="incoming",
+            visible_value="visible",
+            reducer=ReducerRef(name="wf.std.replace"),
+        )
+    ]
+
+    append_lineage_writes(run, scope_id="root", lineage_id="child", writes=writes)
+
+    assert run.lineages["child"].writes[0].incoming_value == "incoming"
+    assert run.lineages["child"].writes[0].visible_value == "visible"
+    assert (
+        lineage_state_view(run, scope_id="root", lineage_id="child")["value"]
+        == "visible"
+    )
+    assert run.state["value"] == "seed"
+    patch = lineage_patch(run, scope_id="root", lineage_id="child")
+    assert patch.writes[0].incoming_value == "incoming"
+    assert patch.writes[0].visible_value == "visible"
+
+
 def _minimal_workflow() -> Workflow:
     return Workflow(
         name="lineage_root",