Function GetTestDirectory

src/leveldb/include/leveldb/env.h:370–372

    return target_->StartThread(f, a);
  }
  Status GetTestDirectory(std::string* path) override {
    return target_->GetTestDirectory(path);
  }
  Status NewLogger(const std::string& fname, Logger** result) override {
    return target_->NewLogger(fname, result);
  }