Can a Judge Testify As a Witness on a Separate Trial ?

In Conti v. Citrin (239 AD2d 251 [1st Dept 1997]) the Judge witnessed an assault between the parties in the Judge's robing room. The Judge was subpoenaed and testified at the separate assault trial. The Judge was then requested to recuse himself prior to the separate postjudgment nonjury proceeding. the court refused to recuse itself, and the Appellate Division affirmed, stating that as a discretionary decision, it was within the personal conscience of the court as the sole arbitrator of discretion, and should not be disturbed unless an actual showing of bias was made by the moving party.