What is the test for disqualifying a judge?

5 Section 170.6 then provided that no judge shall try any action or special proceeding when it is established by an affidavit that he is prejudiced against a party or attorney so that the party or attorney cannot, or believes he cannot, have a fair and impartial trial before such judge. Facts showing prejudice need not be alleged or proved, and, where a timely motion to disqualify is made, supported by an affidavit alleging prejudice, the case or matter, without any further act or proof, must be assigned to another judge for trial or hearing. (See Pappa v. Superior Court, 54 Cal.2d 350, 353, 5 Cal.Rptr. 703, 353 P.2d 311; Jacobs v. Superior Court, 53 Cal.2d 187, 190, 1 Cal.Rptr. 9, 347 P.2d 9.)