Holographic duality acts in the simplest way (classical supergravity, classical strings) at strong 't Hooft coupling, and any direct test thereof requires non-perturbative input. One of the methods that has been instrumental in scrutinizing predictions of holography is localization. Mostly used in the AdS/CFT context, localization provided a number of direct test of the AdS/CFT duality for N=4 super-Yang Mills (SYM) and N=6 super-Chern-Simons theories. \par I will describe how localization methods can be extended to the non-conformal setting, for N=2* mass deformation of N=4 SYM. Firm field-theory predictions at strong coupling can then be confronted with holographic calculations with a variety of probes such as fundamental strings and D-branes. An unexpected novel feature of N=2* is an infinite number of quantum phase transitions accumulating towards strong coupling.\\ \\ (Organizer: IPhT/Ivan Kostov)