"bzr selftest -s bt.per_interbranch Loom" finds 0 tests

[Andrew Bennetts]

$ bzr selftest -s bt.per_interbranch Loom
----------------------------------------------------------------------
Ran 0 tests in 0.000s

This is because the InterLoomBranch branch object doesn't get registered unless bzrlib.plugins.loom.branch is imported, so it isn't included in the per_interbranch scenarios. If you add e.g. "import branch" to loom/__init__.py then you get the expected result:

Ran 81 tests in 3.877s

[Robert Collins (lifeless)]

I haven't looked at the branch, but I'd expect the fix to be importing
the module in the test_suite() function.

However, that may be racy with the global import :(