dieharder is a fairly involved random number/uniform deviate generator tester. It can either test any of its many pre-built and linked generators (basically all of those in the Gnu Scientific Library plus some others) or a potentially random data-set in a file. With file input, it can manage either a variety of ASCII-formatted input or a raw binary bit string. It is thus suitable for use in testing both software RNG's and hardware RNG's. dieharder does all of its work with a standalone, extensible library, libdieharder. Therefore its tests can be integrated into other programs. dieharder encapsulates following random number tests: George Marsaglia's "Diehard" battery of tests, STS (v1.6) from NIST FIPS, Knuth's tests, and more. Check the documentation for complete list of the tests and references where possible. It is intended to be the "Swiss army knife of random number testers", or "the last suite of random number testers you'll ever wear".
See also: dieharder-libs.