func (*passwordSuite) TestSetPasswordsNoArgsNoError(c *gc.C) {
	getCanChange := func() (common.AuthFunc, error) {
		return nil, fmt.Errorf("splat")
	}
	pc := common.NewPasswordChanger(&fakeState{}, getCanChange)
	result, err := pc.SetPasswords(params.EntityPasswords{})
	c.Assert(err, gc.IsNil)
	c.Assert(result.Results, gc.HasLen, 0)
}

// NewProvisionerAPI creates a new server-side ProvisionerAPI facade.
func NewProvisionerAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*ProvisionerAPI, error) {
	if !authorizer.AuthMachineAgent() && !authorizer.AuthEnvironManager() {
		return nil, common.ErrPerm
	}
	getAuthFunc := func() (common.AuthFunc, error) {
		isEnvironManager := authorizer.AuthEnvironManager()
		isMachineAgent := authorizer.AuthMachineAgent()
		authEntityTag := authorizer.GetAuthTag()

		return func(tag names.Tag) bool {
			if isMachineAgent && tag == authEntityTag {
				// A machine agent can always access its own machine.
				return true
			}
			switch tag := tag.(type) {
			case names.MachineTag:
				parentId := state.ParentId(tag.Id())
				if parentId == "" {
					// All top-level machines are accessible by the
					// environment manager.
					return isEnvironManager
				}
				// All containers with the authenticated machine as a
				// parent are accessible by it.
				// TODO(dfc) sometimes authEntity tag is nil, which is fine because nil is
				// only equal to nil, but it suggests someone is passing an authorizer
				// with a nil tag.
				return isMachineAgent && names.NewMachineTag(parentId) == authEntityTag
			default:
				return false
			}
		}, nil
	}
	env, err := st.Environment()
	if err != nil {
		return nil, err
	}
	urlGetter := common.NewToolsURLGetter(env.UUID(), st)
	return &ProvisionerAPI{
		Remover:                common.NewRemover(st, false, getAuthFunc),
		StatusSetter:           common.NewStatusSetter(st, getAuthFunc),
		StatusGetter:           common.NewStatusGetter(st, getAuthFunc),
		DeadEnsurer:            common.NewDeadEnsurer(st, getAuthFunc),
		PasswordChanger:        common.NewPasswordChanger(st, getAuthFunc),
		LifeGetter:             common.NewLifeGetter(st, getAuthFunc),
		StateAddresser:         common.NewStateAddresser(st),
		APIAddresser:           common.NewAPIAddresser(st, resources),
		EnvironWatcher:         common.NewEnvironWatcher(st, resources, authorizer),
		EnvironMachinesWatcher: common.NewEnvironMachinesWatcher(st, resources, authorizer),
		InstanceIdGetter:       common.NewInstanceIdGetter(st, getAuthFunc),
		ToolsFinder:            common.NewToolsFinder(st, st, urlGetter),
		st:                     st,
		resources:              resources,
		authorizer:             authorizer,
		getAuthFunc:            getAuthFunc,
	}, nil
}

func (*passwordSuite) TestSetPasswords(c *gc.C) {
	st := &fakeState{
		entities: map[names.Tag]entityWithError{
			u("x/0"): &fakeAuthenticator{},
			u("x/1"): &fakeAuthenticator{},
			u("x/2"): &fakeAuthenticator{
				err: fmt.Errorf("x2 error"),
			},
			u("x/3"): &fakeAuthenticator{
				fetchError: "x3 error",
			},
			u("x/4"): &fakeUnitAuthenticator{},
			u("x/5"): &fakeMachineAuthenticator{jobs: []state.MachineJob{state.JobHostUnits}},
			u("x/6"): &fakeMachineAuthenticator{jobs: []state.MachineJob{state.JobManageEnviron}},
		},
	}
	getCanChange := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			return tag != names.NewUnitTag("x/0")
		}, nil
	}
	pc := common.NewPasswordChanger(st, getCanChange)
	var changes []params.EntityPassword
	for i := 0; i < len(st.entities); i++ {
		tag := fmt.Sprintf("unit-x-%d", i)
		changes = append(changes, params.EntityPassword{
			Tag:      tag,
			Password: fmt.Sprintf("%spass", tag),
		})
	}
	results, err := pc.SetPasswords(params.EntityPasswords{
		Changes: changes,
	})
	c.Assert(err, gc.IsNil)
	c.Assert(results, jc.DeepEquals, params.ErrorResults{
		Results: []params.ErrorResult{
			{apiservertesting.ErrUnauthorized},
			{nil},
			{&params.Error{Message: "x2 error"}},
			{&params.Error{Message: "x3 error"}},
			{nil},
			{nil},
			{nil},
		},
	})
	c.Check(st.entities[u("x/0")].(*fakeAuthenticator).pass, gc.Equals, "")
	c.Check(st.entities[u("x/1")].(*fakeAuthenticator).pass, gc.Equals, "unit-x-1pass")
	c.Check(st.entities[u("x/2")].(*fakeAuthenticator).pass, gc.Equals, "")
	c.Check(st.entities[u("x/4")].(*fakeUnitAuthenticator).pass, gc.Equals, "unit-x-4pass")
	c.Check(st.entities[u("x/4")].(*fakeUnitAuthenticator).mongoPass, gc.Equals, "")
	c.Check(st.entities[u("x/5")].(*fakeMachineAuthenticator).pass, gc.Equals, "unit-x-5pass")
	c.Check(st.entities[u("x/5")].(*fakeMachineAuthenticator).mongoPass, gc.Equals, "")
	c.Check(st.entities[u("x/6")].(*fakeMachineAuthenticator).pass, gc.Equals, "unit-x-6pass")
	c.Check(st.entities[u("x/6")].(*fakeMachineAuthenticator).mongoPass, gc.Equals, "unit-x-6pass")
}

// NewAPI returns an object implementing an agent API
// with the given authorizer representing the currently logged in client.
func NewAPI(st *state.State, resources *common.Resources, auth common.Authorizer) (*API, error) {
	// Agents are defined to be any user that's not a client user.
	if !auth.AuthMachineAgent() && !auth.AuthUnitAgent() {
		return nil, common.ErrPerm
	}
	getCanChange := func() (common.AuthFunc, error) {
		return auth.AuthOwner, nil
	}
	return &API{
		PasswordChanger: common.NewPasswordChanger(st, getCanChange),
		st:              st,
		auth:            auth,
	}, nil
}

func (*passwordSuite) TestSetPasswordsError(c *gc.C) {
	getCanChange := func() (common.AuthFunc, error) {
		return nil, fmt.Errorf("splat")
	}
	pc := common.NewPasswordChanger(&fakeState{}, getCanChange)
	var changes []params.EntityPassword
	for i := 0; i < 4; i++ {
		tag := fmt.Sprintf("x%d", i)
		changes = append(changes, params.EntityPassword{
			Tag:      tag,
			Password: fmt.Sprintf("%spass", tag),
		})
	}
	_, err := pc.SetPasswords(params.EntityPasswords{Changes: changes})
	c.Assert(err, gc.ErrorMatches, "splat")
}

// NewDeployerAPI creates a new server-side DeployerAPI facade.
func NewDeployerAPI(
	st *state.State,
	resources facade.Resources,
	authorizer facade.Authorizer,
) (*DeployerAPI, error) {
	if !authorizer.AuthMachineAgent() {
		return nil, common.ErrPerm
	}
	getAuthFunc := func() (common.AuthFunc, error) {
		// Get all units of the machine and cache them.
		thisMachineTag := authorizer.GetAuthTag()
		units, err := getAllUnits(st, thisMachineTag)
		if err != nil {
			return nil, err
		}
		// Then we just check if the unit is already known.
		return func(tag names.Tag) bool {
			for _, unit := range units {
				// TODO (thumper): remove the names.Tag conversion when gccgo
				// implements concrete-type-to-interface comparison correctly.
				if names.Tag(names.NewUnitTag(unit)) == tag {
					return true
				}
			}
			return false
		}, nil
	}
	getCanWatch := func() (common.AuthFunc, error) {
		return authorizer.AuthOwner, nil
	}
	return &DeployerAPI{
		Remover:         common.NewRemover(st, true, getAuthFunc),
		PasswordChanger: common.NewPasswordChanger(st, getAuthFunc),
		LifeGetter:      common.NewLifeGetter(st, getAuthFunc),
		StateAddresser:  common.NewStateAddresser(st),
		APIAddresser:    common.NewAPIAddresser(st, resources),
		UnitsWatcher:    common.NewUnitsWatcher(st, resources, getCanWatch),
		StatusSetter:    common.NewStatusSetter(st, getAuthFunc),
		st:              st,
		resources:       resources,
		authorizer:      authorizer,
	}, nil
}