sporadic test failure: storeManagerStateSuite.TestStateWatcher

See http://data.vapour.ws/juju-ci/products/version-2483/run-unit-tests-vivid-amd64/build-297/consoleText.

This appears to be a transient failure. So far I've only seen it on master.

---------------------------------------------------------------------
FAIL: megawatcher_internal_test.go:1561: storeManagerStateSuite.TestStateWatcher

[LOG] 0:00.004 INFO juju.state opening state, mongo addresses: ["localhost:57340"]; entity <nil>
[LOG] 0:00.004 DEBUG juju.state dialing mongo
[LOG] 0:00.005 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.006 DEBUG juju.state connection established
[LOG] 0:00.030 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.030 INFO juju.state initializing environment, owner: "test-admin@local"
[LOG] 0:00.030 INFO juju.state info: &mongo.MongoInfo{Info:mongo.Info{Addrs:[]string{"localhost:57340"}, CACert:"-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----\n"}, Tag:names.Tag(nil), Password:""}
[LOG] 0:00.030 INFO juju.state starting presence watcher
[LOG] 0:00.032 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.110 INFO juju.state opening state, mongo addresses: ["localhost:57340"]; entity <nil>
[LOG] 0:00.110 DEBUG juju.state dialing mongo
[LOG] 0:00.111 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.112 DEBUG juju.state connection established
[LOG] 0:00.118 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.119 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
[LOG] 0:00.419 INFO juju.mongo dialled mongo successfully on address "127.0.0.1:57340"
megawatcher_internal_test.go:1678:
    checkDeltasEqual(c, deltas, []multiwatcher.Delta{{
        Entity: &multiwatcher.MachineInfo{
            Id: "0",
            InstanceId: "i-0",
            Status: multiwatcher.Status("pending"),
            Life: multiwatcher.Life("alive"),
            Series: "trusty",
            Jobs: []multiwatcher.MachineJob{JobManageEnviron.ToParams()},
            Addresses: []network.Address{},
            HardwareCharacteristics: hc,
            HasVote: false,
            WantsVote: true,
        },
    }, {
        Removed: true,
        Entity: &multiwatcher.MachineInfo{
            Id: "1",
            Status: multiwatcher.Status("pending"),
            Life: multiwatcher.Life("alive"),
            Series: "saucy",
            Jobs: []multiwatcher.MachineJob{JobHostUnits.ToParams()},
            Addresses: []network.Address{},
        },
    }, {
        Entity: &multiwatcher.MachineInfo{
            Id: "2",
            Status: multiwatcher.Status("pending"),
            Life: multiwatcher.Life("alive"),
            Series: "quantal",
            Jobs: []multiwatcher.MachineJob{JobHostUnits.ToParams()},
            Addresses: []network.Address{},
            HasVote: false,
            WantsVote: false,
        },
    }, {
        Entity: &multiwatcher.ServiceInfo{
            Name: "wordpress",
            CharmURL: "local:quantal/quantal-wordpress-3",
            OwnerTag: s.owner.String(),
            Life: "alive",
            Config: make(map[string]interface{}),
        },
    }, {
        Entity: &multiwatcher.UnitInfo{
            Name: "wordpress/0",
            Service: "wordpress",
            Series: "quantal",
            MachineId: "2",
            Status: "allocating",
        },
    }})
megawatcher_internal_test.go:1906:
    // Deltas are returned in arbitrary order, so we compare them as maps.
    c.Check(deltaMap(d0), jc.DeepEquals, deltaMap(d1))
... obtained map[interface {}]multiwatcher.EntityInfo = map[interface {}]multiwatcher.EntityInfo{multiwatcher.EntityId{Kind:"machine", Id:"0"}:(*multiwatcher.MachineInfo)(0xc20817da00), multiwatcher.EntityId{Kind:"machine", Id:"1"}:multiwatcher.EntityInfo(nil), multiwatcher.EntityId{Kind:"service", Id:"wordpress"}:(*multiwatcher.ServiceInfo)(0xc208270c60), multiwatcher.EntityId{Kind:"machine", Id:"2"}:(*multiwatcher.MachineInfo)(0xc20817dad0)}
... expected map[interface {}]multiwatcher.EntityInfo = map[interface {}]multiwatcher.EntityInfo{multiwatcher.EntityId{Kind:"machine", Id:"0"}:(*multiwatcher.MachineInfo)(0xc20817dc70), multiwatcher.EntityId{Kind:"machine", Id:"1"}:multiwatcher.EntityInfo(nil), multiwatcher.EntityId{Kind:"machine", Id:"2"}:(*multiwatcher.MachineInfo)(0xc20814c4e0), multiwatcher.EntityId{Kind:"service", Id:"wordpress"}:(*multiwatcher.ServiceInfo)(0xc208270d10), multiwatcher.EntityId{Kind:"unit", Id:"wordpress/0"}:(*multiwatcher.UnitInfo)(0xc20814c5b0)}
... mismatch at top level: length mismatch, 4 vs 5; obtained map[interface {}]multiwatcher.EntityInfo{multiwatcher.EntityId{Kind:"service", Id:"wordpress"}:(*multiwatcher.ServiceInfo)(0xc208270c60), multiwatcher.EntityId{Kind:"machine", Id:"2"}:(*multiwatcher.MachineInfo)(0xc20817dad0), multiwatcher.EntityId{Kind:"machine", Id:"0"}:(*multiwatcher.MachineInfo)(0xc20817da00), multiwatcher.EntityId{Kind:"machine", Id:"1"}:multiwatcher.EntityInfo(nil)}; expected map[interface {}]multiwatcher.EntityInfo{multiwatcher.EntityId{Kind:"service", Id:"wordpress"}:(*multiwatcher.ServiceInfo)(0xc208270d10), multiwatcher.EntityId{Kind:"unit", Id:"wordpress/0"}:(*multiwatcher.UnitInfo)(0xc20814c5b0), multiwatcher.EntityId{Kind:"machine", Id:"0"}:(*multiwatcher.MachineInfo)(0xc20817dc70), multiwatcher.EntityId{Kind:"machine", Id:"1"}:multiwatcher.EntityInfo(nil), multiwatcher.EntityId{Kind:"machine", Id:"2"}:(*multiwatcher.MachineInfo)(0xc20814c4e0)}

[LOG] 0:00.503 INFO juju.testing reset successfully reset admin password
2015-03-25 12:43:05 INFO juju.testing mgo.go:514 reset successfully reset admin password
2015-03-25 12:44:22 INFO juju.testing mgo.go:514 reset successfully reset admin password
2015-03-25 12:45:10 INFO juju.testing mgo.go:514 reset successfully reset admin password
OOPS: 907 passed, 1 FAILED
--- FAIL: TestPackage (451.79 seconds)
FAIL
FAIL github.com/juju/juju/state 452.013s