Typical process of rewiring a house
While I can't speak to your specific situation, in many jurisdictions the electrician is required by local law to install the wiring, leaving the electrical boxes open and without installing outlets, fixtures, and switches. This allows the electrical inspector to check out the wiring (size, number of wires, proper mounting) before the system is closed up. This is called rough-in inspection. Only after you get this preliminary approval is the electrician allowed to mount outlets, switches, etc.

This approach also allows the electrician to check out the continuity of the wiring before he adds devices that may complicate the testing.

Whether this is the case in your jurisdiction depends on local law.