An electrical test at the end of the production requires the complete CAD-data as well as a testing automat which contacts and controls all endpoints. Within the testing automats you difference between the Circuit-Tester and the Flying-Prober. The Flying-Probers have 8 testing-fingers which test the PCBs after net lists.
This technique has the big advantage that every Fine-Pitch can be contacted.

The latest ATG finger testing machines precisely measure all connections of the PCB after your connection list and also spare the surface.  

When using the In-Circuit-Tester the PCBs will be tested with spring bolt populated adapters or very fine so called fixed needle adapters. This technique has the advantage that all testing points can be tested at once and therefore a fast test with an optimal testing depth can be achieved.

Due to staggering today the MCA micro adapters allow the contacting of finest structures of microelectronic.