Fix tests

Author: alexowens90

cpp/arcticdb/version/version_functions.hpp

@@ -222,7 +222,7 @@ inline folly::Future<version_store::TombstoneVersionResult> finalize_tombstone_a
     if (version_map->validate())
         entry->validate();
 
-    version_store::TombstoneVersionResult res{true, entry->head_->id()};
+    version_store::TombstoneVersionResult res{true, entry->stream_id_};
     res.keys_to_delete = std::move(tombstone_result.second);
 
     res.no_undeleted_left = true;
@@ -314,7 +314,11 @@ inline std::optional<AtomKey> load_index_key_from_time(
     LoadStrategy load_strategy{LoadType::FROM_TIME, LoadObjective::UNDELETED_ONLY, from_time};
     auto entry = version_map->check_reload(store, stream_id, load_strategy, __FUNCTION__);
     auto indexes = entry->get_indexes(false);
-    return get_index_key_from_time(from_time, indexes)->to_atom_key(stream_id);
+    if (auto opt_index_key = get_index_key_from_time(from_time, indexes); opt_index_key.has_value()) {
+        return opt_index_key->to_atom_key(stream_id);
+    } else {
+        return std::nullopt;
+    }
 }
 
 inline std::vector<AtomKey> get_index_and_tombstone_keys(