What is the test for alleging bias in a judicial officer?

Second, the mother contends that the judicial officer was biased and references the transcript of a hearing where the court explained its visitation ruling to the minor. The mother's allegation of bias is procedurally barred, however, because the mother did not claim during the six-month status review and section 388 hearing that "the judge should recuse [her]self or that [her] constitutional rights were violated because of judicial bias. 'It is too late to raise the issue for the first time on appeal.' " (People v. Guerra (2006) 37 Cal.4th 1067, 1111, overruled on another ground in People v. Rundle (2008) 43 Cal.4th 76, 151.) The mother's claim also fails on the merits, as there is no evidence in the record that "any judicial . . . bias was so prejudicial that it deprived [the mother] of ' "a fair . . . trial." ' " (Id. at p. 1112.)