provider/maas: test failure because of test isolation failure

[Roger Peppe]

instanceTest.TestAddresses and instanceTest.TestAddressesMissing both fail on my machine
because inst.Addresses calls network.ResolvableHostnames and my IP provider successfully
resolves any IP address, including "testing.invalid".

--- FAIL: TestMAAS (0.06s)
FAIL: instance_test.go:51: instanceTest.TestAddresses

[LOG] 0:00.000 DEBUG juju.testing setting feature flags: address-allocation
instance_test.go:68:
    c.Check(addr, gc.DeepEquals, expected)
... obtained []network.Address = []network.Address{public:testing.invalid, local-cloud:testing.invalid, public:1.2.3.4, link-local:fe80::d806:dbff:fe23:1199}
... expected []network.Address = []network.Address{public:1.2.3.4, link-local:fe80::d806:dbff:fe23:1199}

----------------------------------------------------------------------
FAIL: instance_test.go:71: instanceTest.TestAddressesMissing

[LOG] 0:00.000 DEBUG juju.testing setting feature flags: address-allocation
instance_test.go:83:
    c.Check(addr, gc.DeepEquals, []network.Address{})
... obtained []network.Address = []network.Address{public:testing.invalid, local-cloud:testing.invalid}
... expected []network.Address = []network.Address{}

exit status 1

[Andrew McDermott (frobware)]

I tested this with 8.8.8.8 as my provider and it doesn't, though I see that my ISPs resolver does.

[Andrew McDermott (frobware)]

If you're currently blocked by this could you change your host to use 8.8.8.8 as a resolver?

[Andrew McDermott (frobware)]

Quick patch - needs verification this is the direction we want, but passes when I use my ISPs resolver. Without the patch, and with my ISPs revolver, it fails.

[Andrew McDermott (frobware)]

RB - http://reviews.vapour.ws/r/3137/

[Andrew McDermott (frobware)]

Based on some discussions with mgz and dimitern I am going to rework this.

From IRC:

<mgz> the tests actually query a real dns server, so the solution is changing the value that escapes testing to fail more, rather than correctly isolating the tests from the runner's dns setup?

[Andrew McDermott (frobware)]

RB for 1.25 - http://reviews.vapour.ws/r/3327/

Assuming that's OK then I will revert the original "fix" on master (commit 8a3d71c3aaf12ce80ca84bceb6c87013ae7e584e) and forward port this fix from 1.25 to master.

[Andrew McDermott (frobware)]

RB for master: http://reviews.vapour.ws/r/3329/