The ngspice distribution is accompanied by a suite of test input and output files, located in the directory ngspice/tests. Originally this suite was meant to see if ngspice with all models was made and installed properly. It is started by

$ make check

from within your compilation and development shell. A sequence of simulations is thus started, its outputs compared to given output files by comparisons string by string. This feature is momentarily used only to check for the BSIM3 model (11.2.10) and the XSPICE extension (12). Several other input files located in directory ngspice/tests may serve as light-weight examples for invoking devices and simple circuits.

Today's very complex device models (BSIM4 (see 11.2.11), HiSIM (see 11.2.15) and others) require a different strategy for verification. Under development for ngspice is the CMC Regression test by Colin McAndrew, which accompanies every new model. These tests cover a large range of different DC, AC and noise simulations with different geometry ranges and operating conditions and are more meaningful the transient simulations with their step size dependencies. A major advantage is the scalability of the diff comparisons, which check for equality within a given tolerance. A set of Perl modules cares for input, output and comparisons of the models. Currently BSIM3, BSIM4, BSIMSOI4, HiSIM, and HiSIM_HV models implement the new test. You may invoke it by running the command given above or by

$ make -i check 2>&1 | tee results

-i will make make to ignore any errors, tee will provide console output as well as printing to file 'results'. Be aware that under MS Windows you will need the console binary (see 32.2.5) to run the CMC tests, and you have to have Perl installed!