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 *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"})
	assertJoined(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)
	assertJoined(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)
	assertJoined(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)
	assertJoined(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.
	assertJoined(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 *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 *stateSuite) TestWatchEnvironMachines(c *gc.C) {
	w, err := s.firewaller.WatchEnvironMachines()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewStringsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange(s.machines[0].Id(), s.machines[1].Id(), s.machines[2].Id())

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

	// Change the life cycle of last machine.
	err = otherMachine.EnsureDead()
	c.Assert(err, gc.IsNil)
	wc.AssertChange(otherMachine.Id())

	// 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.machines[0].Id(), instance.LXC)
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()

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

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 *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 *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 *RelationUnitSuite) TestCoalesceWatchScope(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)

	// ru1 and ru2 enter; check changes observed together.
	err := pr.ru1.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	err = pr.ru2.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	s.assertScopeChange(c, w0, []string{"riak/1", "riak/2"}, nil)
	s.assertNoScopeChange(c, w0)

	// ru1 leaves and re-enters; check no change observed.
	err = pr.ru1.LeaveScope()
	c.Assert(err, gc.IsNil)
	err = pr.ru1.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	s.assertNoScopeChange(c, w0)

	// ru1 and ru2 leave; check changes observed together.
	err = pr.ru1.LeaveScope()
	c.Assert(err, gc.IsNil)
	err = pr.ru2.LeaveScope()
	c.Assert(err, gc.IsNil)
	s.assertScopeChange(c, w0, nil, []string{"riak/1", "riak/2"})
	s.assertNoScopeChange(c, w0)
}

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 *machinerSuite) TestWatch(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.machiner.Watch(args)
	c.Assert(err, gc.IsNil)
	c.Assert(result, gc.DeepEquals, params.NotifyWatchResults{
		Results: []params.NotifyWatchResult{
			{NotifyWatcherId: "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].NotifyWatcherId, 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 *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 *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 *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 *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()
}

func (s *relationUnitSuite) TestWatchRelationUnits(c *gc.C) {
	// Enter scope with mysqlUnit.
	myRelUnit, err := s.stateRelation.Unit(s.mysqlUnit)
	c.Assert(err, gc.IsNil)
	err = myRelUnit.EnterScope(nil)
	c.Assert(err, gc.IsNil)
	s.assertInScope(c, myRelUnit, true)

	apiRel, err := s.uniter.Relation(s.stateRelation.Tag())
	c.Assert(err, gc.IsNil)
	apiUnit, err := s.uniter.Unit("unit-wordpress-0")
	c.Assert(err, gc.IsNil)
	apiRelUnit, err := apiRel.Unit(apiUnit)
	c.Assert(err, gc.IsNil)

	w, err := apiRelUnit.Watch()
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewRelationUnitsWatcherC(c, s.BackingState, w)

	// Initial event.
	wc.AssertChange([]string{"mysql/0"}, nil)

	// Leave scope with mysqlUnit, check it's detected.
	err = myRelUnit.LeaveScope()
	c.Assert(err, gc.IsNil)
	s.assertInScope(c, myRelUnit, false)
	wc.AssertChange(nil, []string{"mysql/0"})

	// Non-change is not reported.
	err = myRelUnit.LeaveScope()
	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 *firewallerSuite) TestWatch(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.Watch(args)
	c.Assert(err, gc.IsNil)
	c.Assert(result, jc.DeepEquals, params.NotifyWatchResults{
		Results: []params.NotifyWatchResult{
			{Error: apiservertesting.ErrUnauthorized},
			{NotifyWatcherId: "1"},
			{NotifyWatcherId: "2"},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.NotFoundError(`unit "foo/0"`)},
			{Error: apiservertesting.NotFoundError(`service "bar"`)},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
			{Error: apiservertesting.ErrUnauthorized},
		},
	})

	// Verify the resources were registered and stop when done.
	c.Assert(s.resources.Count(), gc.Equals, 2)
	c.Assert(result.Results[1].NotifyWatcherId, gc.Equals, "1")
	watcher1 := s.resources.Get("1")
	defer statetesting.AssertStop(c, watcher1)
	c.Assert(result.Results[2].NotifyWatcherId, gc.Equals, "2")
	watcher2 := s.resources.Get("2")
	defer statetesting.AssertStop(c, watcher2)

	// Check that the Watch has consumed the initial event ("returned" in
	// the Watch call)
	wc1 := statetesting.NewNotifyWatcherC(c, s.State, watcher1.(state.NotifyWatcher))
	wc1.AssertNoChange()
	wc2 := statetesting.NewNotifyWatcherC(c, s.State, watcher2.(state.NotifyWatcher))
	wc2.AssertNoChange()
}

func (s *FilterSuite) TestResolvedEvents(c *gc.C) {
	f, err := newFilter(s.uniter, s.unit.Tag())
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, f)

	resolvedAsserter := coretesting.ContentAsserterC{
		C:       c,
		Precond: func() { s.BackingState.StartSync() },
		Chan:    f.ResolvedEvents(),
	}
	resolvedAsserter.AssertNoReceive()

	// Request an event; no interesting event is available.
	f.WantResolvedEvent()
	resolvedAsserter.AssertNoReceive()

	// Change the unit in an irrelevant way; no events.
	err = s.unit.SetStatus(params.StatusError, "blarg", nil)
	c.Assert(err, gc.IsNil)
	resolvedAsserter.AssertNoReceive()

	// Change the unit's resolved to an interesting value; new event received.
	err = s.unit.SetResolved(state.ResolvedRetryHooks)
	c.Assert(err, gc.IsNil)
	assertChange := func(expect params.ResolvedMode) {
		rm := resolvedAsserter.AssertOneReceive().(params.ResolvedMode)
		c.Assert(rm, gc.Equals, expect)
	}
	assertChange(params.ResolvedRetryHooks)

	// Ask for the event again, and check it's resent.
	f.WantResolvedEvent()
	assertChange(params.ResolvedRetryHooks)

	// Clear the resolved status *via the filter*; check not resent...
	err = f.ClearResolved()
	c.Assert(err, gc.IsNil)
	resolvedAsserter.AssertNoReceive()

	// ...even when requested.
	f.WantResolvedEvent()
	resolvedAsserter.AssertNoReceive()

	// Induce several events; only latest state is reported.
	err = s.unit.SetResolved(state.ResolvedRetryHooks)
	c.Assert(err, gc.IsNil)
	err = f.ClearResolved()
	c.Assert(err, gc.IsNil)
	err = s.unit.SetResolved(state.ResolvedNoHooks)
	c.Assert(err, gc.IsNil)
	assertChange(params.ResolvedNoHooks)
}

func (s *EnvironWatcherTests) TestWatchForEnvironConfigChanges(c *gc.C) {
	envConfig, err := s.state.EnvironConfig()
	c.Assert(err, gc.IsNil)

	w, err := s.facade.WatchForEnvironConfigChanges()
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewNotifyWatcherC(c, s.state, w)

	// Initial event.
	wc.AssertOneChange()

	// Change the environment configuration by updating an existing attribute, check it's detected.
	newAttrs := map[string]interface{}{"logging-config": "juju=ERROR"}
	err = s.state.UpdateEnvironConfig(newAttrs, nil, nil)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Change the environment configuration by adding a new attribute, check it's detected.
	newAttrs = map[string]interface{}{"foo": "bar"}
	err = s.state.UpdateEnvironConfig(newAttrs, nil, nil)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Change the environment configuration by removing an attribute, check it's detected.
	err = s.state.UpdateEnvironConfig(map[string]interface{}{}, []string{"foo"}, nil)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Change it back to the original config.
	oldAttrs := map[string]interface{}{"logging-config": envConfig.AllAttrs()["logging-config"]}
	err = s.state.UpdateEnvironConfig(oldAttrs, nil, nil)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

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

func (s *machineUpgraderSuite) TestWatchAPIVersion(c *gc.C) {
	w, err := s.st.WatchAPIVersion(s.rawMachine.Tag())
	c.Assert(err, gc.IsNil)
	defer statetesting.AssertStop(c, w)
	wc := statetesting.NewNotifyWatcherC(c, s.BackingState, w)
	// Initial event
	wc.AssertOneChange()
	vers := version.MustParse("10.20.34")
	err = statetesting.SetAgentVersion(s.BackingState, vers)
	c.Assert(err, gc.IsNil)
	// One change noticing the new version
	wc.AssertOneChange()
	// Setting the version to the same value doesn't trigger a change
	err = statetesting.SetAgentVersion(s.BackingState, vers)
	c.Assert(err, gc.IsNil)
	wc.AssertNoChange()
	vers = version.MustParse("10.20.35")
	err = statetesting.SetAgentVersion(s.BackingState, vers)
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()
	statetesting.AssertStop(c, w)
	wc.AssertClosed()
}

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

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

	// Initial event.
	wc.AssertOneChange()

	// Change something and check it's detected.
	err = s.service.SetExposed()
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

	// Destroy the service and check it's detected.
	err = s.service.Destroy()
	c.Assert(err, gc.IsNil)
	wc.AssertOneChange()

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