test(infonet): cover invalid majority-time timestamps

backend/services/infonet/tests/test_time_validity_invalid_timestamps.py

@@ -0,0 +1,30 @@
+"""Regression coverage for malformed chain timestamps."""
+
+from services.infonet.time_validity import chain_majority_time, is_event_too_future
+
+
+def _event(node_id: str, timestamp):
+    return {"node_id": node_id, "timestamp": timestamp}
+
+
+def test_chain_majority_time_ignores_malformed_and_nonfinite_timestamps():
+    chain = [
+        _event("valid-a", 10.0),
+        _event("bad-text", "not-a-timestamp"),
+        _event("bad-nan", float("nan")),
+        _event("bad-inf", float("inf")),
+        _event("valid-b", 20.0),
+    ]
+
+    assert chain_majority_time(chain) == 15.0
+
+
+def test_chain_majority_time_accepts_finite_numeric_strings():
+    chain = [_event("a", "10.5"), _event("b", "20.5")]
+
+    assert chain_majority_time(chain) == 15.5
+
+
+def test_future_check_does_not_treat_nonfinite_timestamp_as_valid():
+    assert not is_event_too_future(_event("a", float("nan")), chain_time=100.0)
+    assert not is_event_too_future(_event("a", float("inf")), chain_time=100.0)