histedit: add checkunfinished support (
issue3955)
The tests contain a couple corner cases where workarounds are now
required. Strictly speaking, these are behavior regressions, but of an
extremely obscure and marginal sort. Commits or updates in the middle
of a histedit would have almost always been fairly serious user error.
try:
import coverage
getattr(coverage, 'process_startup', lambda: None)()
except ImportError:
pass