No, you are not necessarily required to testify in court, although it is your right to do so if you want. Speaking with a lawyer will help you decide whether or not testifying is the appropriate action to help your defense.
Criminal defense attorneys serve clients who have been charged with crimes ranging from minor to major offenses. These crimes include murder, manslaughter, arson, assault, DUI/DWI, fraud, identity theft, child pornography, and sex crimes.
Many non-criminal legal cases are settled outside of court and never actually reach a trial. Criminal defense attorneys, however, try more cases in a courtroom and before a judge and jury than any other type of attorney.