The understanding of black hole mergers in general relativity heavily relies on numerical results in the test-mass limit in order to model the multipolar waveform, the radiation reaction, the plunge dynamics, and quasi-normal-modes excitation. A successful approach combines perturbation theory (Teukolsky equation) with the effective-one-body dynamics for the test-body source. In this framework, hyperboloidal foliations are the key technical element that allows accurate numerical solutions of the time-domain (2+1) Teukolsky equation. The talk reviews methods and results of this "test-mass laboratory" as well as recent applications of hyperboloidal foliation and perturbation theory for building gravitational wave extraction algorithms in numerical relativity.