What is the test for determining whether an employee is an employee or an independent contractor?

Labor Code section 2750.5, which establishes rules for determining whether a worker performing services for which a license is required is an employee or an independent contractor. To prove that a worker is an independent contractor requires showing that the worker controls the manner of performing the work, that the worker is customarily engaged in an independently established business, and that the independent contractor status is bona fide and not a subterfuge. (Ibid.) Labor Code section 2750.5 goes on to state that, in addition to these factors, "any person performing any function or activity for which a license is required pursuant to Chapter 9 (commencing with [s]ection 7000) of Division 3 of the Business and Professions Code shall hold a valid contractors' license as a condition of having independent contractor status." (Lab. Code, 2750.5, subd. (c), italics added.) Courts have interpreted this last statement to mean that a worker "lacking the requisite license may not be an independent contractor." (State Compensation Ins. Fund v. Workers' Comp. Appeals Bd. (1985) 40 Cal.3d 5, 15.) Or, in other words, "the presumption that the person who employs the unlicensed contractor is the employer is conclusive." (Cedillo v. Workers' Comp. Appeals Bd. (2003) 106 Cal.App.4th 227, 233.)