We suggest a self-testing teleportation configuration for photon qubits bas
ed on a Mach-Zehnder interferometer. That is, Bob can tell how well the inp
ut state has been teleported without knowing what that input state was. One
could imagine building a "locked" teleporter based on this configuration.
The analysis is performed for continuous variable teleportation but the arr
angement could be applied equally to discrete manipulations.