Protect against absent global IPython instance. This basically applies most of the changes to ultraTB made by Brian in the reorg branch here: http://bazaar.launchpad.net/~ipython-dev/ipython/module-reorg/revision/1225 To our duplicate copies of ultraTB (the duplication is already gone in the reorg branch). This now means that the trial-based tests run fine if executed as trial IPython OR trial IPython.kernel where as the latter form was failing before. The reason why the former used to work was that a hidden global ipython is created, *upon import*, by ipdoctest. That will stay for now, but I've made it bug https://bugs.launchpad.net/ipython/+bug/409096 marked as critical for 0.11 that I'll need to fix.