These are obsolete. Tests are run with 'tox', or by running 'trial
allmydata' from a populated virtualenv. A populated virtualenv is also
the right way to get a repl: just run 'python'.
refs ticket:2735
Most of the CLI tests don't care about the actual shares. Configuring
the test client to use k=N=1 reduces the runtime from 180s to 90s on my
laptop.
A few tests *do* care, like test_check (which delete some shares, then
assert that 'tahoe check' shows the damage). These still use k=3/N=10.
