A rigid casing provides support and protection for two separate fiber optic jumper cables of a fiber optic test set and which may be wound on two separate spools for extension and retraction relative to the casing. A selected length of one of the cables may be extended from the casing and connected to a part of a fiber optic circuit to be tested, following which a selected length of the other cable may be extended from the casing and connected to another part of the circuit. The spools are capable of rotation about a common axis with and relative to one another. The cables have confronting ends at the axis of rotation of the spools and in axial alignment so that light energy emitted from either cable may be received by the other without interruption.