K.R.
Well for me with my 2nd son it took until day 45 to get a positive pregnancy test. I was a unique circumstance, however, because it was only my second ovulation post-breastfeeding, and I think my cycles were longer than the average 28-30 days. I have heard of this happening, however, to other women - where the blood and/or urine test didn't show positive until a bit after that standard missed period on your 30th cycle day.
I would encourage her to keep testing every few days until it either shows up positive, or she gets her period. I was also want to mention I have never shown symptoms that early either.
Good luck to her :)
K