[Monotone-devel] "mtn serve" in tests

[Zack Weinberg]

Unfortunately, in some environments we need to be able to disable all
use of the network - even the loopback interface - in the test suite.
For this to work reliably, we need to stick to three simple rules for
use of "mtn serve":

1. Don't use "mtn serve" to test anything other than netsync.
2. Don't test anything besides netsync in a netsync test.
3. All netsync tests must begin by loading common/netsync.lua.

I've just pushed a rev that fixes existing violations of (1); everyone
currently follows (2) and (3), but they bear repeating. netsync.lua
contains logic to automatically skip the test when use of the network
has been disabled.

I've also pushed a change that, in addition to the existing
"check_net" automatic mechanism for disabling network tests, lets you
manually suppress them by setting the environment variable
DISABLE_NETWORK_TESTS.  (The automatic mechanism has, sadly, proved
unreliable.)

zw