how to unit test on the ATS

[魏晋]

Hi
    The ATS is greate, and I want to study the souce code of the ATS
recently. I found some unit test codes in the ATS sources, for example
the CacheTest.cc, test_Cache.i files in the cache suddirectory. Are
these files still useable?
    Maybe I need to do some unit tests on the ATS for better
understanding how it woks, but I cound not find a easy way to come
throught it.  Can anybody tell me how the ATS coders do their unit
test?
    My Version is 2.1.3-unstalbe.