[Piglit] Is it normal to see piglit quick.tests results changing?

[Scott Tsai]

Hi,

I noticed that if I run piglit quick.tests twice, some tests would
change from pass to fail and vice versa:
ex:
   piglit-run /usr/lib64/piglit/tests/quick.tests result0
   piglit-run /usr/lib64/piglit/tests/quick.tests result1
   piglit-summary-html summary results0 results1
   xdg-open summary/index.html

I see these tests changing:
   fbo-3d
   fbo-sys-blit
   fbo-sys-blit
   bgra-sec-color-pointer
   scissor-clear
   (... quite a bit more ...)
Is this expected?

I uploaded the piglit-summary-html report to
http://scottt.tw/piglit-summary/index.html
This is on an Intel Sandy Bridge machine running Fedora 16
(kernel 3.1, mesa-7.11 from distro packages):
http://www.smolts.org/client/show_all/pub_19218c58-fdb9-4c7e-81d7-c0d1e5b8c17d

Matěj Cepl plans to use piglit for internal QA at Red Hat and I'm
helping him getting it packaged for Fedora. Could anyone share some
experience on using piglit for regression testing?