test(engine): retain static schema names across shared factor rows

crates/fidc-core/src/numeric_factors.rs

@@ -436,6 +436,19 @@ mod tests {
         assert!(rows.iter().all(|row| matches!(row.storage, Storage::Owned(_))));
     }
 
+    #[test]
+    fn shared_schema_borrows_a_static_key_even_after_a_dynamic_equal_key() {
+        const KEY: &str = "a_shared_factor_name_longer_than_inline_storage";
+        let mut rows = (0..64).map(|index| NumericFactorMap::from([
+            (if index == 0 { Cow::Owned(KEY.to_string()) } else { Cow::Borrowed(KEY) }, index as f64),
+            (Cow::Borrowed("another"), 2.0),
+        ])).collect::<Vec<_>>();
+        assert_eq!(NumericFactorMap::share_rows(rows.iter_mut()), rows.len());
+        for row in &rows {
+            assert_eq!(row.keys().find(|key| key.as_str() == KEY).unwrap().as_static_str(), Some(KEY));
+        }
+    }
+
     #[test]
     fn compact_keys_inline_dynamic_names_and_keep_long_static_storage() {
         const LONG: &str = "a_long_static_factor_identifier_that_must_remain_borrowed";