message: Don't implicitly return data for TestIndexer.
diff: @@ -52,8 +52,12 @@ struct TestIndexer : IIndexer {
  const std::vector<FileContents>& file_contents,
  PerformanceImportFile* perf) {
  auto it = indexes.find(file);
  - if (it == indexes.end())
  + if (it == indexes.end()) {
  + // Don't return any indexes for unexpected data.
  + assert(false && "no indexes");
  return {};
  + }
  +
  // FIXME: allow user to control how many times we return the index for a
  // specific file (atm it is always 1)
  auto result = std::move(it->second);
  