prove -l -j2 creates race condition

[mohawk2]

The Tutorial says you can be "relaxed" and use prove -l.

However, if your module has two tests, prove -l -j2 t/t1.t t2.t will create a race condition as two processes will race to build the module, and sadness will ensue. make will not (as far as I can tell) cause this problem, so I think this should be documented as the way forward: make test TEST_FILES="t/t1.t t/t2.t". Or, some per-module locking that still allows concurrent building of several modules.