How is a motion for a continuance reviewed on appeal?

"'The trial court's denial of a motion for continuance is reviewed for abuse of discretion.' [Citation.] 'There are no mechanical tests for deciding when a denial of a continuance is so arbitrary as to violate due process. The answer must be found in the circumstances present in every case, particularly in the reasons presented to the trial judge at the time the request is denied.' [Citations.] In reviewing the decision to deny a continuance, '[o]ne factor to consider is whether a continuance would be useful. [Citation.]' [Citation.]" (People v. Mungia (2008) 44 Cal.4th 1101, 1118.) Moreover, ""'a ruling or decision, itself correct in law, will not be disturbed on appeal merely because given for a wrong reason. If right upon any theory of the laws applicable to the case, it must be sustained regardless of the considerations which may have moved the trial court to its conclusion." [Citation]' [Citation.]" (People v. Zapien (1993) 4 Cal.4th 929, 976.)