func (s *serviceSuite) TestWatchRelations(c *gc.C) {
	w, err := s.apiService.WatchRelations()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewStringsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange()
	wc.AssertNoChange()

	// Change something other than the lifecycle and make sure it's
	// not detected.
	err = s.wordpressService.SetExposed()
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	// Add another service and relate it to wordpress,
	// check it's detected.
	s.addMachineServiceCharmAndUnit(c, "mysql")
	rel := s.addRelation(c, "wordpress", "mysql")
	wc.AssertChange(rel.String())

	// Destroy the relation and check it's detected.
	err = rel.Destroy()
	c.Assert(err, gc.IsNil)
	wc.AssertChange(rel.String())
	wc.AssertNoChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *UnitSuite) TestWatchUnit(c *gc.C) {
	preventUnitDestroyRemove(c, s.unit)
	w := s.unit.Watch()
	defer testing.AssertStop(c, w)

	// Initial event.
	wc := testing.NewNotifyWatcherC(c, s.State, w)
	wc.AssertOneChange()

	// Make one change (to a separate instance), check one event.
	unit, err := s.State.Unit(s.unit.Name())
	c.Assert(err, gc.IsNil)
	s.setAssignedMachineAddresses(c, unit)
	wc.AssertOneChange()

	// Make two changes, check one event.
	err = unit.SetPassword("arble-farble-dying-yarble")
	c.Assert(err, gc.IsNil)
	err = unit.Destroy()
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Stop, check closed.
	testing.AssertStop(c, w)
	wc.AssertClosed()

	// Remove unit, start new watch, check single event.
	err = unit.EnsureDead()
	c.Assert(err, gc.IsNil)
	err = unit.Remove()
	c.Assert(err, gc.IsNil)
	w = s.unit.Watch()
	defer testing.AssertStop(c, w)
	testing.NewNotifyWatcherC(c, s.State, w).AssertOneChange()
}

func (s *APIAddresserTests) TestWatchAPIHostPorts(c *gc.C) {
	expectServerAddrs := [][]instance.HostPort{{{
		Address: instance.NewAddress("0.1.2.3", instance.NetworkUnknown),
		Port:    1234,
	}}}
	err := s.state.SetAPIHostPorts(expectServerAddrs)
	c.Assert(err, gc.IsNil)

	w, err := s.facade.WatchAPIHostPorts()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)

	wc := statetesting.NewNotifyWatcherC(c, s.state, w)

	// Initial event.
	wc.AssertOneChange()

	// Change the state addresses and check that we get a notification
	expectServerAddrs[0][0].Value = "0.1.99.99"

	err = s.state.SetAPIHostPorts(expectServerAddrs)
	c.Assert(err, gc.IsNil)

	wc.AssertOneChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *machineSuite) TestWatchUnits(c *gc.C) {
	w, err := s.apiMachine.WatchUnits()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewStringsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange("wordpress/0")
	wc.AssertNoChange()

	// Change something other than the life cycle and make sure it's
	// not detected.
	err = s.machines[0].SetPassword("foo")
	c.Assert(err, gc.ErrorMatches, "password is only 3 bytes long, and is not a valid Agent password")
	wc.AssertNoChange()

	err = s.machines[0].SetPassword("foo-12345678901234567890")
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	// Unassign unit 0 from the machine and check it's detected.
	err = s.units[0].UnassignFromMachine()
	c.Assert(err, gc.IsNil)
	wc.AssertChange("wordpress/0")
	wc.AssertNoChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *deployerSuite) TestWatchUnits(c *gc.C) {
	machine, err := s.st.Machine(s.machine.Tag())
	c.Assert(err, gc.IsNil)
	w, err := machine.WatchUnits()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewStringsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange("mysql/0", "logging/0")
	wc.AssertNoChange()

	// Change something other than the lifecycle and make sure it's
	// not detected.
	err = s.subordinate.SetPassword("foo")
	c.Assert(err, gc.ErrorMatches, "password is only 3 bytes long, and is not a valid Agent password")
	wc.AssertNoChange()

	err = s.subordinate.SetPassword("foo-12345678901234567890")
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	// Make the subordinate dead and check it's detected.
	err = s.subordinate.EnsureDead()
	c.Assert(err, gc.IsNil)
	wc.AssertChange("logging/0")
	wc.AssertNoChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *ServiceSuite) TestWatchService(c *gc.C) {
	w := s.mysql.Watch()
	defer testing.AssertStop(c, w)

	// Initial event.
	wc := testing.NewNotifyWatcherC(c, s.State, w)
	wc.AssertOneChange()

	// Make one change (to a separate instance), check one event.
	service, err := s.State.Service(s.mysql.Name())
	c.Assert(err, gc.IsNil)
	err = service.SetExposed()
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Make two changes, check one event.
	err = service.ClearExposed()
	c.Assert(err, gc.IsNil)
	err = service.SetCharm(s.charm, true)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Stop, check closed.
	testing.AssertStop(c, w)
	wc.AssertClosed()

	// Remove service, start new watch, check single event.
	err = service.Destroy()
	c.Assert(err, gc.IsNil)
	w = s.mysql.Watch()
	defer testing.AssertStop(c, w)
	testing.NewNotifyWatcherC(c, s.State, w).AssertOneChange()
}

func (s *unitSuite) TestWatch(c *gc.C) {
	c.Assert(s.apiUnit.Life(), gc.Equals, params.Alive)

	w, err := s.apiUnit.Watch()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewNotifyWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertOneChange()

	// Change something other than the life cycle and make sure it's
	// not detected.
	err = s.units[0].SetStatus(params.StatusStarted, "not really", nil)
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	// Make the unit dead and check it's detected.
	err = s.units[0].EnsureDead()
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *RelationUnitSuite) TestPeerWatchScope(c *gc.C) {
	pr := NewPeerRelation(c, s.State)

	// Test empty initial event.
	w0 := pr.ru0.WatchScope()
	defer testing.AssertStop(c, w0)
	s.assertScopeChange(c, w0, nil, nil)
	s.assertNoScopeChange(c, w0)

	// ru0 enters; check no change, but settings written.
	assertNotInScope(c, pr.ru0)
	err := pr.ru0.EnterScope(map[string]interface{}{"foo": "bar"})
	c.Assert(err, gc.IsNil)
	s.assertNoScopeChange(c, w0)
	node, err := pr.ru0.Settings()
	c.Assert(err, gc.IsNil)
	c.Assert(node.Map(), gc.DeepEquals, map[string]interface{}{"foo": "bar"})
	assertInScope(c, pr.ru0)

	// ru1 enters; check change is observed.
	assertNotInScope(c, pr.ru1)
	err = pr.ru1.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	s.assertScopeChange(c, w0, []string{"riak/1"}, nil)
	s.assertNoScopeChange(c, w0)
	assertInScope(c, pr.ru1)

	// ru1 enters again, check no problems and no changes.
	err = pr.ru1.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	s.assertNoScopeChange(c, w0)
	assertInScope(c, pr.ru1)

	// Stop watching; ru2 enters.
	testing.AssertStop(c, w0)
	assertNotInScope(c, pr.ru2)
	err = pr.ru2.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	assertInScope(c, pr.ru2)

	// Start watch again, check initial event.
	w0 = pr.ru0.WatchScope()
	defer testing.AssertStop(c, w0)
	s.assertScopeChange(c, w0, []string{"riak/1", "riak/2"}, nil)
	s.assertNoScopeChange(c, w0)

	// ru1 leaves; check event.
	assertInScope(c, pr.ru1)
	err = pr.ru1.LeaveScope()
	c.Assert(err, gc.IsNil)
	s.assertScopeChange(c, w0, nil, []string{"riak/1"})
	s.assertNoScopeChange(c, w0)
	assertNotInScope(c, pr.ru1)

	// ru1 leaves again; check no problems and no changes.
	err = pr.ru1.LeaveScope()
	c.Assert(err, gc.IsNil)
	s.assertNoScopeChange(c, w0)
	assertNotInScope(c, pr.ru1)
}

func (s *provisionerSuite) TestWatchEnvironMachines(c *gc.C) {
	w, err := s.provisioner.WatchEnvironMachines()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewStringsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange(s.machine.Id())

	// Add another 2 machines make sure they are detected.
	otherMachine, err := s.State.AddMachine("quantal", state.JobHostUnits)
	c.Assert(err, gc.IsNil)
	otherMachine, err = s.State.AddMachine("quantal", state.JobHostUnits)
	c.Assert(err, gc.IsNil)
	wc.AssertChange("1", "2")

	// Change the lifecycle of last machine.
	err = otherMachine.EnsureDead()
	c.Assert(err, gc.IsNil)
	wc.AssertChange("2")

	// Add a container and make sure it's not detected.
	template := state.MachineTemplate{
		Series: "quantal",
		Jobs:   []state.MachineJob{state.JobHostUnits},
	}
	_, err = s.State.AddMachineInsideMachine(template, s.machine.Id(), instance.LXC)
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *withoutStateServerSuite) TestWatchMachineErrorRetry(c *gc.C) {
	s.PatchValue(&provisioner.ErrorRetryWaitDelay, 2*coretesting.ShortWait)
	c.Assert(s.resources.Count(), gc.Equals, 0)

	_, err := s.provisioner.WatchMachineErrorRetry()
	c.Assert(err, gc.IsNil)

	// Verify the resources were registered and stop them when done.
	c.Assert(s.resources.Count(), gc.Equals, 1)
	resource := s.resources.Get("1")
	defer statetesting.AssertStop(c, resource)

	// Check that the Watch has consumed the initial event ("returned"
	// in the Watch call)
	wc := statetesting.NewNotifyWatcherC(c, s.State, resource.(state.NotifyWatcher))
	wc.AssertNoChange()

	// We should now get a time triggered change.
	wc.AssertOneChange()

	// Make sure WatchMachineErrorRetry fails with a machine agent login.
	anAuthorizer := s.authorizer
	anAuthorizer.MachineAgent = true
	anAuthorizer.EnvironManager = false
	aProvisioner, err := provisioner.NewProvisionerAPI(s.State, s.resources, anAuthorizer)
	c.Assert(err, gc.IsNil)

	result, err := aProvisioner.WatchMachineErrorRetry()
	c.Assert(err, gc.ErrorMatches, "permission denied")
	c.Assert(result, gc.DeepEquals, params.NotifyWatchResult{})
}

func (s *FilterSuite) TestServiceDeath(c *gc.C) {
	f, err := newFilter(s.uniter, s.unit.Tag())
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, f)
	dyingAsserter := coretesting.NotifyAsserterC{
		C:       c,
		Precond: func() { s.BackingState.StartSync() },
		Chan:    f.UnitDying(),
	}
	dyingAsserter.AssertNoReceive()

	err = s.unit.SetStatus(params.StatusStarted, "", nil)
	c.Assert(err, gc.IsNil)
	err = s.wordpress.Destroy()
	c.Assert(err, gc.IsNil)

	timeout := time.After(coretesting.LongWait)
loop:
	for {
		select {
		case <-f.UnitDying():
			break loop
		case <-time.After(coretesting.ShortWait):
			s.BackingState.StartSync()
		case <-timeout:
			c.Fatalf("dead not detected")
		}
	}
	err = s.unit.Refresh()
	c.Assert(err, gc.IsNil)
	c.Assert(s.unit.Life(), gc.Equals, state.Dying)

	// Can't set s.wordpress to Dead while it still has units.
}

func (s *uniterSuite) TestWatchConfigSettings(c *gc.C) {
	err := s.wordpressUnit.SetCharmURL(s.wpCharm.URL())
	c.Assert(err, gc.IsNil)

	c.Assert(s.resources.Count(), gc.Equals, 0)

	args := params.Entities{Entities: []params.Entity{
		{Tag: "unit-mysql-0"},
		{Tag: "unit-wordpress-0"},
		{Tag: "unit-foo-42"},
	}}
	result, err := s.uniter.WatchConfigSettings(args)
	c.Assert(err, gc.IsNil)
	c.Assert(result, gc.DeepEquals, params.NotifyWatchResults{
		Results: []params.NotifyWatchResult{
			{Error: apiservertesting.ErrUnauthorized},
			{NotifyWatcherId: "1"},
			{Error: apiservertesting.ErrUnauthorized},
		},
	})

	// Verify the resource was registered and stop when done
	c.Assert(s.resources.Count(), gc.Equals, 1)
	resource := s.resources.Get("1")
	defer statetesting.AssertStop(c, resource)

	// Check that the Watch has consumed the initial event ("returned" in
	// the Watch call)
	wc := statetesting.NewNotifyWatcherC(c, s.State, resource.(state.NotifyWatcher))
	wc.AssertNoChange()
}

func (s *deployerSuite) TestWatchUnits(c *gc.C) {
	c.Assert(s.resources.Count(), gc.Equals, 0)

	args := params.Entities{Entities: []params.Entity{
		{Tag: "machine-1"},
		{Tag: "machine-0"},
		{Tag: "machine-42"},
	}}
	result, err := s.deployer.WatchUnits(args)
	c.Assert(err, gc.IsNil)
	sort.Strings(result.Results[0].Changes)
	c.Assert(result, gc.DeepEquals, params.StringsWatchResults{
		Results: []params.StringsWatchResult{
			{Changes: []string{"logging/0", "mysql/0"}, StringsWatcherId: "1"},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
		},
	})

	// Verify the resource was registered and stop when done
	c.Assert(s.resources.Count(), gc.Equals, 1)
	c.Assert(result.Results[0].StringsWatcherId, gc.Equals, "1")
	resource := s.resources.Get("1")
	defer statetesting.AssertStop(c, resource)

	// Check that the Watch has consumed the initial event ("returned" in
	// the Watch call)
	wc := statetesting.NewStringsWatcherC(c, s.State, resource.(state.StringsWatcher))
	wc.AssertNoChange()
}

func (s *authorisedKeysSuite) TestWatchAuthorisedKeys(c *gc.C) {
	args := params.Entities{
		Entities: []params.Entity{
			{Tag: s.rawMachine.Tag()},
			{Tag: s.unrelatedMachine.Tag()},
			{Tag: "machine-42"},
		},
	}
	results, err := s.keyupdater.WatchAuthorisedKeys(args)
	c.Assert(err, gc.IsNil)
	c.Assert(results, gc.DeepEquals, params.NotifyWatchResults{
		Results: []params.NotifyWatchResult{
			{NotifyWatcherId: "1"},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
		},
	})
	c.Assert(results.Results[0].NotifyWatcherId, gc.Not(gc.Equals), "")
	c.Assert(results.Results[0].Error, gc.IsNil)
	resource := s.resources.Get(results.Results[0].NotifyWatcherId)
	c.Assert(resource, gc.NotNil)

	w := resource.(state.NotifyWatcher)
	wc := statetesting.NewNotifyWatcherC(c, s.State, w)
	wc.AssertNoChange()

	s.setAuthorizedKeys(c, "key1\nkey2")

	wc.AssertOneChange()
	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *withoutStateServerSuite) TestWatchEnvironMachines(c *gc.C) {
	c.Assert(s.resources.Count(), gc.Equals, 0)

	got, err := s.provisioner.WatchEnvironMachines()
	c.Assert(err, gc.IsNil)
	want := params.StringsWatchResult{
		StringsWatcherId: "1",
		Changes:          []string{"0", "1", "2", "3", "4"},
	}
	c.Assert(got.StringsWatcherId, gc.Equals, want.StringsWatcherId)
	c.Assert(got.Changes, jc.SameContents, want.Changes)

	// Verify the resources were registered and stop them when done.
	c.Assert(s.resources.Count(), gc.Equals, 1)
	resource := s.resources.Get("1")
	defer statetesting.AssertStop(c, resource)

	// Check that the Watch has consumed the initial event ("returned"
	// in the Watch call)
	wc := statetesting.NewStringsWatcherC(c, s.State, resource.(state.StringsWatcher))
	wc.AssertNoChange()

	// Make sure WatchEnvironMachines fails with a machine agent login.
	anAuthorizer := s.authorizer
	anAuthorizer.MachineAgent = true
	anAuthorizer.EnvironManager = false
	aProvisioner, err := provisioner.NewProvisionerAPI(s.State, s.resources, anAuthorizer)
	c.Assert(err, gc.IsNil)

	result, err := aProvisioner.WatchEnvironMachines()
	c.Assert(err, gc.ErrorMatches, "permission denied")
	c.Assert(result, gc.DeepEquals, params.StringsWatchResult{})
}

func (s *firewallerSuite) TestWatchUnits(c *gc.C) {
	c.Assert(s.resources.Count(), gc.Equals, 0)

	args := addFakeEntities(params.Entities{Entities: []params.Entity{
		{Tag: s.machines[0].Tag()},
		{Tag: s.service.Tag()},
		{Tag: s.units[0].Tag()},
	}})
	result, err := s.firewaller.WatchUnits(args)
	c.Assert(err, gc.IsNil)
	c.Assert(result, jc.DeepEquals, params.StringsWatchResults{
		Results: []params.StringsWatchResult{
			{Changes: []string{"wordpress/0"}, StringsWatcherId: "1"},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.NotFoundError("machine 42")},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
		},
	})

	// Verify the resource was registered and stop when done
	c.Assert(s.resources.Count(), gc.Equals, 1)
	c.Assert(result.Results[0].StringsWatcherId, gc.Equals, "1")
	resource := s.resources.Get("1")
	defer statetesting.AssertStop(c, resource)

	// Check that the Watch has consumed the initial event ("returned" in
	// the Watch call)
	wc := statetesting.NewStringsWatcherC(c, s.State, resource.(state.StringsWatcher))
	wc.AssertNoChange()
}

func (s *watcherSuite) TestWatchUnitsKeepsEvents(c *gc.C) {
	// Create two services, relate them, and add one unit to each - a
	// principal and a subordinate.
	mysql := s.AddTestingService(c, "mysql", s.AddTestingCharm(c, "mysql"))
	logging := s.AddTestingService(c, "logging", s.AddTestingCharm(c, "logging"))
	eps, err := s.State.InferEndpoints([]string{"mysql", "logging"})
	c.Assert(err, gc.IsNil)
	rel, err := s.State.AddRelation(eps...)
	c.Assert(err, gc.IsNil)
	principal, err := mysql.AddUnit()
	c.Assert(err, gc.IsNil)
	err = principal.AssignToMachine(s.rawMachine)
	c.Assert(err, gc.IsNil)
	relUnit, err := rel.Unit(principal)
	c.Assert(err, gc.IsNil)
	err = relUnit.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	subordinate, err := logging.Unit("logging/0")
	c.Assert(err, gc.IsNil)

	// Call the Deployer facade's WatchUnits for machine-0.
	var results params.StringsWatchResults
	args := params.Entities{Entities: []params.Entity{{Tag: s.rawMachine.Tag()}}}
	err = s.stateAPI.Call("Deployer", "", "WatchUnits", args, &results)
	c.Assert(err, gc.IsNil)
	c.Assert(results.Results, gc.HasLen, 1)
	result := results.Results[0]
	c.Assert(result.Error, gc.IsNil)

	// Start a StringsWatcher and check the initial event.
	w := watcher.NewStringsWatcher(s.stateAPI, result)
	wc := statetesting.NewStringsWatcherC(c, s.State, w)
	wc.AssertChange("mysql/0", "logging/0")
	wc.AssertNoChange()

	// Now, without reading any changes advance the lifecycle of both
	// units, inducing an update server-side after each two changes to
	// ensure they're reported as separate events over the API.
	err = subordinate.EnsureDead()
	c.Assert(err, gc.IsNil)
	s.BackingState.StartSync()
	err = subordinate.Remove()
	c.Assert(err, gc.IsNil)
	err = principal.EnsureDead()
	c.Assert(err, gc.IsNil)
	s.BackingState.StartSync()

	// Expect these changes as 2 separate events, so that
	// nothing gets lost.
	wc.AssertChange("logging/0")
	wc.AssertChange("mysql/0")
	wc.AssertNoChange()

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *unitUpgraderSuite) TestWatchAPIVersion(c *gc.C) {
	w, err := s.st.WatchAPIVersion(s.rawUnit.Tag())
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewNotifyWatcherC(c, s.BackingState, w)
	// Initial event
	wc.AssertOneChange()
	vers := version.MustParseBinary("10.20.34-quantal-amd64")
	err = s.rawMachine.SetAgentVersion(vers)
	c.Assert(err, gc.IsNil)
	// One change noticing the new version
	wc.AssertOneChange()
	vers = version.MustParseBinary("10.20.35-quantal-amd64")
	err = s.rawMachine.SetAgentVersion(vers)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()
	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *unitSuite) TestWatchConfigSettings(c *gc.C) {
	// Make sure WatchConfigSettings returns an error when
	// no charm URL is set, as its state counterpart does.
	w, err := s.apiUnit.WatchConfigSettings()
	c.Assert(err, gc.ErrorMatches, "unit charm not set")

	// Now set the charm and try again.
	err = s.apiUnit.SetCharmURL(s.wordpressCharm.URL())
	c.Assert(err, gc.IsNil)

	w, err = s.apiUnit.WatchConfigSettings()
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewNotifyWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertOneChange()

	// Update config a couple of times, check a single event.
	err = s.wordpressService.UpdateConfigSettings(charm.Settings{
		"blog-title": "superhero paparazzi",
	})
	c.Assert(err, gc.IsNil)
	err = s.wordpressService.UpdateConfigSettings(charm.Settings{
		"blog-title": "sauceror central",
	})
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Non-change is not reported.
	err = s.wordpressService.UpdateConfigSettings(charm.Settings{
		"blog-title": "sauceror central",
	})
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

	// NOTE: This test is not as exhaustive as the one in state,
	// because the watcher is already tested there. Here we just
	// ensure we get the events when we expect them and don't get
	// them when they're not expected.

	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

func (s *keyupdaterSuite) TestWatchAuthorisedKeys(c *gc.C) {
	watcher, err := s.keyupdater.WatchAuthorisedKeys(s.rawMachine.Tag())
	c.Assert(err, gc.IsNil)
	defer testing.AssertStop(c, watcher)
	wc := testing.NewNotifyWatcherC(c, s.BackingState, watcher)
	// Initial event
	wc.AssertOneChange()

	s.setAuthorisedKeys(c, "key1\nkey2")
	// One change noticing the new version
	wc.AssertOneChange()
	// Setting the version to the same value doesn't trigger a change
	s.setAuthorisedKeys(c, "key1\nkey2")
	wc.AssertNoChange()

	s.setAuthorisedKeys(c, "key1\nkey2\nkey3")
	wc.AssertOneChange()
	testing.AssertStop(c, watcher)
	wc.AssertClosed()
}