OK that's cool. In the mean time I'll do a new run o doctesting - I haven't done a full one on that build yet I had limited myself to key tests. And I have just found:

frb15@p2n14-c /hpc/scratch/frb15/sandbox/sage-5.7.beta4 :./sage -t --long -force_lib devel/sage/sage/plot/plot3d/list_plot3d.py
sage -t --long -force_lib "devel/sage/sage/plot/plot3d/list_plot3d.py"
[16.4 s]
----------------------------------------------------------------------
All tests passed!
Total time for all tests: 16.6 seconds

So somehow this one got fixed. I had misread the test results from beta3+numpy-1.7. So updating description again.