(a) Except as provided in subsection (b) below, every mechanic applying for [licensure] shall have passed the appropriate certification test provided for in this chapter.
(b) Notwithstanding any provision of this chapter, any person who has been engaged as a motor vehicle mechanic for a period of at least two years prior to January 1, 1976, and who has applied for [licensure] as a motor vehicle mechanic under this chapter on or before June 30, 1976, shall not be required to take the certification test prescribed in this chapter prior to [licensure].