Notably, Bolton has the same attorney as does Charles Kupperman. Kupperman was the United States Deputy National Security Advisor for President Trump from January to September 2019. Kupperman was "subpoenaed" by the House, however:
The Trump administration, through White House counsel Pat Cipollone, directed Kupperman in writing not to comply with the House subpoena claiming "constitutional immunity" would protect him. Subsequently, Kupperman filed a lawsuit asking a federal judge to decide whether or not he must comply with the House subpoena or the Trump Administration's request to not testify. Kupperman's lawyer argued that he is faced with "irreconcilable commands" between the legislative and executive branches of government which can only be decided by the judicial branch.
Since the House is currently not attempting to enforce these "subpoenas" it's likely that Bolton will not be testifying.