A method for testing an optical-electrical device under test, DUT, using an automated testing equipment, ATE, system, the method comprising: placing the optical-electrical DUT in a socket within a docking plate; passively aligning a load board optical interface between a load board of the ATE system and a mount assembly of the ATE system, a top-side of the load board supporting the optical-electrical DUT such that an electrical interface side of the optical-electrical DUT interfaces with electrical paths on the top-side of the load board to communicate one or more electrical signals from the optical-electrical DUT, the load board optical interface passively aligned by passively aligning a load board optical port of the load board with a first mount assembly optical port of the mount assembly using a receiver feature of the mount assembly that interlocks with an extruded feature of the load board; passively aligning an optical device interface between the mount assembly and the optical-electrical DUT to communicate one or more optical signals generated by the optical-electrical DUT, the optical device interface passively aligned by passively aligning a second mount assembly optical port of the mount assembly with an optical port of the optical-electrical DUT that is on an optical interface side of the optical-electrical DUT that is opposite of the electrical interface side that faces the load board using physical features of the mount assembly that interlock with congruent interlocking features on the docking plate; and analyzing the one or more electrical signals while analyzing the one or more optical signals from the optical-electrical DUT using the ATE system, the one or more electrical signals analyzed by an electrical test device of the ATE system that receives the one or more electrical signals from the electrical paths of the load board, the one or more optical signals analyzed by an optical test device of the ATE system that receives the one or more optical signals via propagation through the optical device interface and the load board optical interface. placing the optical-electrical DUT in a socket within a docking plate; passively aligning a load board optical interface between a load board of the ATE system and a mount assembly of the ATE system, a top-side of the load board supporting the optical-electrical DUT such that an electrical interface side of the optical-electrical DUT interfaces with electrical paths on the top-side of the load board to communicate one or more electrical signals from the optical-electrical DUT, the load board optical interface passively aligned by passively aligning a load board optical port of the load board with a first mount assembly optical port of the mount assembly using a receiver feature of the mount assembly that interlocks with an extruded feature of the load board; passively aligning an optical device interface between the mount assembly and the optical-electrical DUT to communicate one or more optical signals generated by the optical-electrical DUT, the optical device interface passively aligned by passively aligning a second mount assembly optical port of the mount assembly with an optical port of the optical-electrical DUT that is on an optical interface side of the optical-electrical DUT that is opposite of the electrical interface side that faces the load board using physical features of the mount assembly that interlock with congruent interlocking features on the docking plate; and analyzing the one or more electrical signals while analyzing the one or more optical signals from the optical-electrical DUT using the ATE system, the one or more electrical signals analyzed by an electrical test device of the ATE system that receives the one or more electrical signals from the electrical paths of the load board, the one or more optical signals analyzed by an optical test device of the ATE system that receives the one or more optical signals via propagation through the optical device interface and the load board optical interface.