-bash-4.2$ swrng -dd -fn STDOUT -nb 1200000000 | rngtest
rngtest 6
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

rngtest: starting FIPS tests...
rngtest: entropy source drained
rngtest: bits received from input: 9600000000
rngtest: FIPS 140-2 successes: 479584
rngtest: FIPS 140-2 failures: 415
rngtest: FIPS 140-2(2001-10-10) Monobit: 50
rngtest: FIPS 140-2(2001-10-10) Poker: 51
rngtest: FIPS 140-2(2001-10-10) Runs: 153
rngtest: FIPS 140-2(2001-10-10) Long run: 163
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=2.468; avg=136.906; max=19073.486)Mibits/s
rngtest: FIPS tests speed: (min=16.687; avg=151.641; max=235.475)Mibits/s
rngtest: Program run time: 127405487 microseconds