test: cover ttl clearing in _update_metadata_fields (#6703)

Adds unit coverage requested in review: - clearing a finite ttl to None or timedelta(0) now writes a zero Duration (previously silently dropped) - a finite-to-finite ttl update is preserved _update_metadata_fields uses no instance state, so it is exercised directly via the class, mirroring the FeatureView/FileSource/Field construction used elsewhere in the unit tests. Signed-off-by: saket3395 <sakettulsan95@gmail.com>
ntkathole · Aug 14, 2026 · Aug 6, 2026 · Aug 6, 2026 · Aug 11, 2026 · Aug 14, 2026
commit cc340e87b775bae24af106a74611fead18bc5c5f
@@ -0,0 +1,53 @@
+"""Unit tests for Registry._update_metadata_fields TTL handling (issue #6703).
+
+Re-applying a FeatureView with its ttl cleared to ``None`` or
+``timedelta(0)`` (both the documented ways to express "no ttl") used to be
+silently dropped, because the update was gated on ``updated_fv.ttl`` being
+truthy -- and both of those values are falsy.
+
+``_update_metadata_fields`` does not use any instance state, so it is exercised
+directly via the class here rather than standing up a full registry backend.
+"""
+
+from datetime import timedelta
+
+import pytest
+
+from feast.entity import Entity
+from feast.feature_view import FeatureView
+from feast.field import Field
+from feast.infra.offline_stores.file_source import FileSource
+from feast.infra.registry.registry import Registry
+from feast.types import Float32
+
+
+def _feature_view(ttl):
+    return FeatureView(
+        name="fv",
+        entities=[Entity(name="e", join_keys=["e_id"])],
+        schema=[Field(name="f1", dtype=Float32)],
+        source=FileSource(path="file://feast/*", timestamp_field="ts_col"),
+        ttl=ttl,
+    )
+
+
+@pytest.mark.parametrize("cleared_ttl", [None, timedelta(0)])
+def test_update_metadata_fields_clears_ttl(cleared_ttl):
+    existing_proto = _feature_view(timedelta(days=10)).to_proto()
+    # sanity: the existing view starts with a finite ttl
+    assert existing_proto.spec.ttl.ToNanoseconds() != 0
+
+    updated_fv = _feature_view(cleared_ttl)
+    Registry._update_metadata_fields(None, existing_proto, updated_fv)
+
+    # the cleared ttl (None / timedelta(0)) must now be reflected as "no ttl"
+    assert existing_proto.spec.ttl.ToNanoseconds() == 0
+
+
+def test_update_metadata_fields_preserves_finite_ttl():
+    existing_proto = _feature_view(timedelta(days=10)).to_proto()
+
+    updated_fv = _feature_view(timedelta(days=3))
+    Registry._update_metadata_fields(None, existing_proto, updated_fv)
+
+    assert existing_proto.spec.ttl.ToTimedelta() == timedelta(days=3)