DejaGnu is the regression testing framework for the gnu project (http://www.gnu.org/). It is used for gcc, gdb, and a host of other well known GNU programs.
It is based on TclExpect (http://expect.nist.gov/), which is in turn based on Tcl (ToolCommandLanguage, http://www.scriptics.com/).
Many old copies of DejaGnu are floating around the net. Rob Savoye of CygnusSolutions is the current maintainer. It was maintained on SourceForge for a while, but moved back to http://www.gnu.org/software/dejagnu/.
There has not been a new release in quite a while, although the snapshots are quite stable.