Steerable needles offer the potential to turn corners during insertion, thereby avoiding obstacles, reducing tip placement error and enabling a less invasive access to challenging anatomical locations. In this paper, we describe an experimental testbed designed to facilitate experiments with several popular steering mechanisms. One such mechanism makes use of asymmetric forces generated by a bevel tip for actuating steerable needles, and another uses multiple concentric precurved tubes that can change the needle shaft shape by rotating within one another and extending telescopically. The experimental testbed consists of a new robotic actuation unit for controlling axial rotation and linear translation of multiple tubes. It also includes stereo-optical cameras and a magnetic tracking system for the feedback of needle shape and tip location. The setup can be used in future work for model validation and closed-loop feedback control of steerable needles and cannulae.