hello mentors,
I had found the same problem as Aman is facing some days before actually, I forgot to intimate about this thing earlier,
inside test-font.sh, there is a function written xvfbRunAndScreenShot, it will show error and only blank png's will be generated, as far as there is no ../freetype2-demos/bin/ftgrid directory found in our demos program, and there is no branch in demos for GSoC's Gregs works. It will only work when ftgrid file will get merge to the demos repo.
I have found the solution and is running that way but if it is working without the ftgrid file please let me know the way.
thanks,