func (s *bootstrapSuite) TestInitializeStateFailsSecondTime(c *gc.C) {
	dataDir := c.MkDir()

	configParams := agent.AgentConfigParams{
		Paths:             agent.Paths{DataDir: dataDir},
		Tag:               names.NewMachineTag("0"),
		UpgradedToVersion: jujuversion.Current,
		StateAddresses:    []string{s.mgoInst.Addr()},
		CACert:            testing.CACert,
		Password:          testing.DefaultMongoPassword,
		Model:             testing.ModelTag,
	}
	cfg, err := agent.NewAgentConfig(configParams)
	c.Assert(err, jc.ErrorIsNil)
	cfg.SetStateServingInfo(params.StateServingInfo{
		APIPort:        5555,
		StatePort:      s.mgoInst.Port(),
		Cert:           "foo",
		PrivateKey:     "bar",
		SharedSecret:   "baz",
		SystemIdentity: "qux",
	})
	expectHW := instance.MustParseHardware("mem=2048M")
	mcfg := agentbootstrap.BootstrapMachineConfig{
		BootstrapConstraints: constraints.MustParse("mem=1024M"),
		Jobs:                 []multiwatcher.MachineJob{multiwatcher.JobManageModel},
		InstanceId:           "i-bootstrap",
		Characteristics:      expectHW,
	}
	envAttrs := dummy.SampleConfig().Delete("admin-secret").Merge(testing.Attrs{
		"agent-version": jujuversion.Current.String(),
	})
	envCfg, err := config.New(config.NoDefaults, envAttrs)
	c.Assert(err, jc.ErrorIsNil)

	hostedModelConfigAttrs := map[string]interface{}{
		"name": "hosted",
		"uuid": utils.MustNewUUID().String(),
	}

	adminUser := names.NewLocalUserTag("agent-admin")
	st, _, err := agentbootstrap.InitializeState(
		adminUser, cfg, envCfg, hostedModelConfigAttrs, mcfg,
		mongo.DefaultDialOpts(), state.Policy(nil),
	)
	c.Assert(err, jc.ErrorIsNil)
	st.Close()

	st, _, err = agentbootstrap.InitializeState(adminUser, cfg, envCfg, nil, mcfg, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err == nil {
		st.Close()
	}
	c.Assert(err, gc.ErrorMatches, "failed to initialize mongo admin user: cannot set admin password: not authorized .*")
}

func (s *BootstrapSuite) TestInitialPassword(c *gc.C) {
	machineConf, cmd, err := s.initBootstrapCommand(c, nil, "--env-config", s.b64yamlEnvcfg, "--instance-id", string(s.instanceId))
	c.Assert(err, jc.ErrorIsNil)

	err = cmd.Run(nil)
	c.Assert(err, jc.ErrorIsNil)

	info := &mongo.MongoInfo{
		Info: mongo.Info{
			Addrs:  []string{gitjujutesting.MgoServer.Addr()},
			CACert: testing.CACert,
		},
	}

	// Check we can log in to mongo as admin.
	// TODO(dfc) does passing nil for the admin user name make your skin crawl ? mine too.
	info.Tag, info.Password = nil, testPasswordHash()
	st, err := state.Open(testing.EnvironmentTag, info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	defer st.Close()

	// We're running Mongo with --noauth; let's explicitly verify
	// that we can login as that user. Even with --noauth, an
	// explicit Login will still be verified.
	adminDB := st.MongoSession().DB("admin")
	err = adminDB.Login("admin", "invalid-password")
	c.Assert(err, gc.ErrorMatches, "auth fail(s|ed)")
	err = adminDB.Login("admin", info.Password)
	c.Assert(err, jc.ErrorIsNil)

	// Check that the admin user has been given an appropriate
	// password
	u, err := st.User(names.NewLocalUserTag("admin"))
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(u.PasswordValid(testPassword), jc.IsTrue)

	// Check that the machine configuration has been given a new
	// password and that we can connect to mongo as that machine
	// and that the in-mongo password also verifies correctly.
	machineConf1, err := agent.ReadConfig(agent.ConfigPath(machineConf.DataDir(), names.NewMachineTag("0")))
	c.Assert(err, jc.ErrorIsNil)

	stateinfo, ok := machineConf1.MongoInfo()
	c.Assert(ok, jc.IsTrue)
	st, err = state.Open(testing.EnvironmentTag, stateinfo, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	defer st.Close()

	m, err := st.Machine("0")
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(m.HasVote(), jc.IsTrue)
}

func (s *bootstrapSuite) TestInitializeStateFailsSecondTime(c *gc.C) {
	dataDir := c.MkDir()

	pwHash := utils.UserPasswordHash(testing.DefaultMongoPassword, utils.CompatSalt)
	configParams := agent.AgentConfigParams{
		Paths:             agent.Paths{DataDir: dataDir},
		Tag:               names.NewMachineTag("0"),
		UpgradedToVersion: version.Current.Number,
		StateAddresses:    []string{s.mgoInst.Addr()},
		CACert:            testing.CACert,
		Password:          pwHash,
		Environment:       testing.EnvironmentTag,
	}
	cfg, err := agent.NewAgentConfig(configParams)
	c.Assert(err, jc.ErrorIsNil)
	cfg.SetStateServingInfo(params.StateServingInfo{
		APIPort:        5555,
		StatePort:      s.mgoInst.Port(),
		Cert:           "foo",
		PrivateKey:     "bar",
		SharedSecret:   "baz",
		SystemIdentity: "qux",
	})
	expectConstraints := constraints.MustParse("mem=1024M")
	expectHW := instance.MustParseHardware("mem=2048M")
	mcfg := agent.BootstrapMachineConfig{
		Constraints:     expectConstraints,
		Jobs:            []multiwatcher.MachineJob{multiwatcher.JobManageEnviron},
		InstanceId:      "i-bootstrap",
		Characteristics: expectHW,
	}
	envAttrs := dummy.SampleConfig().Delete("admin-secret").Merge(testing.Attrs{
		"agent-version": version.Current.Number.String(),
		"state-id":      "1", // needed so policy can Open config
	})
	envCfg, err := config.New(config.NoDefaults, envAttrs)
	c.Assert(err, jc.ErrorIsNil)

	adminUser := names.NewLocalUserTag("agent-admin")
	st, _, err := agent.InitializeState(adminUser, cfg, envCfg, mcfg, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	st.Close()

	st, _, err = agent.InitializeState(adminUser, cfg, envCfg, mcfg, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err == nil {
		st.Close()
	}
	c.Assert(err, gc.ErrorMatches, "failed to initialize mongo admin user: cannot set admin password: not authorized .*")
}

func (c *MigrateCommand) Run(ctx *cmd.Context) (err error) {

	defer func() {
		if err != nil {
			fmt.Fprintf(ctx.Stdout, "error stack:\n"+errors.ErrorStack(err))
		}
	}()

	loggo.GetLogger("juju").SetLogLevel(loggo.DEBUG)
	conf, err := agent.ReadConfig(agent.ConfigPath(c.dataDir, c.machineTag))
	if err != nil {
		return err
	}

	info, ok := conf.MongoInfo()
	if !ok {
		return errors.Errorf("no state info available")
	}
	st, err := state.Open(conf.Model(), info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err != nil {
		return err
	}
	defer st.Close()

	if c.operation == "export" {
		return c.exportModel(ctx, st)
	}

	return c.importModel(ctx, st)

}

// Run implements cmd.Command.
func (c *dumpLogsCommand) Run(ctx *cmd.Context) error {
	config := c.agentConfig.CurrentConfig()
	info, ok := config.MongoInfo()
	if !ok {
		return errors.New("no database connection info available (is this a controller host?)")
	}

	st0, err := state.Open(config.Environment(), info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err != nil {
		return errors.Annotate(err, "failed to connect to database")
	}
	defer st0.Close()

	envs, err := st0.AllEnvironments()
	if err != nil {
		return errors.Annotate(err, "failed to look up environments")
	}
	for _, env := range envs {
		err := c.dumpLogsForEnv(ctx, st0, env.EnvironTag())
		if err != nil {
			return errors.Annotatef(err, "failed to dump logs for environment %s", env.UUID())
		}
	}

	return nil
}

// fixEnvironment undoes the work of invalidateEnvironment.
func (s *CommonProvisionerSuite) fixEnvironment(c *gc.C) error {
	st, err := state.Open(s.MongoInfo(c), mongo.DefaultDialOpts(), state.Policy(nil))
	c.Assert(err, gc.IsNil)
	defer st.Close()
	attrs := map[string]interface{}{"type": s.cfg.AllAttrs()["type"]}
	return st.UpdateEnvironConfig(attrs, nil, nil)
}

func (s *BootstrapSuite) TestInitializeEnvironmentToolsNotFound(c *gc.C) {
	// bootstrap with 1.99.1 but there will be no tools so version will be reset.
	envcfg, err := s.envcfg.Apply(map[string]interface{}{
		"agent-version": "1.99.1",
	})
	c.Assert(err, jc.ErrorIsNil)
	b64yamlEnvcfg := b64yaml(envcfg.AllAttrs()).encode()

	hw := instance.MustParseHardware("arch=amd64 mem=8G")
	_, cmd, err := s.initBootstrapCommand(c, nil, "--env-config", b64yamlEnvcfg, "--instance-id", string(s.instanceId), "--hardware", hw.String())
	c.Assert(err, jc.ErrorIsNil)
	err = cmd.Run(nil)
	c.Assert(err, jc.ErrorIsNil)

	st, err := state.Open(testing.EnvironmentTag, &mongo.MongoInfo{
		Info: mongo.Info{
			Addrs:  []string{gitjujutesting.MgoServer.Addr()},
			CACert: testing.CACert,
		},
		Password: testPasswordHash(),
	}, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	defer st.Close()

	cfg, err := st.EnvironConfig()
	c.Assert(err, jc.ErrorIsNil)
	vers, ok := cfg.AgentVersion()
	c.Assert(ok, jc.IsTrue)
	c.Assert(vers.String(), gc.Equals, "1.99.0")
}

func (s *environSuite) TestInvalidConfig(c *gc.C) {
	var oldType string
	oldType = s.Environ.Config().AllAttrs()["type"].(string)

	// Create an invalid config by taking the current config and
	// tweaking the provider type.
	info := s.MongoInfo(c)
	opts := mongo.DefaultDialOpts()
	st2, err := state.Open(info, opts, state.Policy(nil))
	c.Assert(err, gc.IsNil)
	defer st2.Close()
	err = st2.UpdateEnvironConfig(map[string]interface{}{"type": "unknown"}, nil, nil)
	c.Assert(err, gc.IsNil)

	w := st2.WatchForEnvironConfigChanges()
	defer stopWatcher(c, w)
	done := make(chan environs.Environ)
	go func() {
		env, err := worker.WaitForEnviron(w, st2, nil)
		c.Check(err, gc.IsNil)
		done <- env
	}()
	// Wait for the loop to process the invalid configuratrion
	<-worker.LoadedInvalid

	st2.UpdateEnvironConfig(map[string]interface{}{
		"type":   oldType,
		"secret": "environ_test",
	}, nil, nil)

	env := <-done
	c.Assert(env, gc.NotNil)
	c.Assert(env.Config().AllAttrs()["secret"], gc.Equals, "environ_test")
}

// dialAndLogin returns a mongo session logged in as a user with administrative
// privileges
func dialAndLogin(mongoInfo *mongo.MongoInfo, callArgs retry.CallArgs) (mgoSession, mgoDb, error) {
	var session *mgo.Session
	opts := mongo.DefaultDialOpts()
	callArgs.Func = func() error {
		// Try to connect, retry a few times until the db comes up.
		var err error
		session, err = mongo.DialWithInfo(mongoInfo.Info, opts)
		if err == nil {
			return nil
		}
		logger.Errorf("cannot open mongo connection: %v", err)
		return err
	}
	if err := retry.Call(callArgs); err != nil {
		return nil, nil, errors.Annotate(err, "error dialing mongo to resume HA")
	}
	admin := session.DB("admin")
	if mongoInfo.Tag != nil {
		if err := admin.Login(mongoInfo.Tag.String(), mongoInfo.Password); err != nil {
			return nil, nil, errors.Annotatef(err, "cannot log in to admin database as %q", mongoInfo.Tag)
		}
	} else if mongoInfo.Password != "" {
		if err := admin.Login(mongo.AdminUser, mongoInfo.Password); err != nil {
			return nil, nil, errors.Annotate(err, "cannot log in to admin database")
		}
	}
	return session, admin, nil
}

// newState returns a new State that uses the given environment.
// The environment must have already been bootstrapped.
func newState(environ environs.Environ, mongoInfo *mongo.MongoInfo) (*state.State, error) {
	config := environ.Config()
	password := config.AdminSecret()
	if password == "" {
		return nil, fmt.Errorf("cannot connect without admin-secret")
	}
	modelTag := names.NewModelTag(config.UUID())

	mongoInfo.Password = password
	opts := mongo.DefaultDialOpts()
	st, err := state.Open(modelTag, mongoInfo, opts, environs.NewStatePolicy())
	if errors.IsUnauthorized(errors.Cause(err)) {
		// We try for a while because we might succeed in
		// connecting to mongo before the state has been
		// initialized and the initial password set.
		for a := redialStrategy.Start(); a.Next(); {
			st, err = state.Open(modelTag, mongoInfo, opts, environs.NewStatePolicy())
			if !errors.IsUnauthorized(errors.Cause(err)) {
				break
			}
		}
		if err != nil {
			return nil, err
		}
	} else if err != nil {
		return nil, err
	}
	if err := updateSecrets(environ, st); err != nil {
		st.Close()
		return nil, fmt.Errorf("unable to push secrets: %v", err)
	}
	return st, nil
}

func (s *BootstrapSuite) TestSetConstraints(c *gc.C) {
	tcons := constraints.Value{Mem: uint64p(2048), CpuCores: uint64p(2)}
	_, cmd, err := s.initBootstrapCommand(c, nil,
		"--env-config", s.b64yamlEnvcfg,
		"--instance-id", string(s.instanceId),
		"--constraints", tcons.String(),
	)
	c.Assert(err, jc.ErrorIsNil)
	err = cmd.Run(nil)
	c.Assert(err, jc.ErrorIsNil)

	st, err := state.Open(testing.EnvironmentTag, &mongo.MongoInfo{
		Info: mongo.Info{
			Addrs:  []string{gitjujutesting.MgoServer.Addr()},
			CACert: testing.CACert,
		},
		Password: testPasswordHash(),
	}, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	defer st.Close()
	cons, err := st.EnvironConstraints()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(cons, gc.DeepEquals, tcons)

	machines, err := st.AllMachines()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(machines, gc.HasLen, 1)
	cons, err = machines[0].Constraints()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(cons, gc.DeepEquals, tcons)
}

func tryOpenState(modelTag names.ModelTag, info *mongo.MongoInfo) error {
	st, err := state.Open(modelTag, info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err == nil {
		st.Close()
	}
	return err
}

// invalidateEnvironment alters the environment configuration
// so the Settings returned from the watcher will not pass
// validation.
func (s *CommonProvisionerSuite) invalidateEnvironment(c *gc.C) {
	st, err := state.Open(s.MongoInfo(c), mongo.DefaultDialOpts(), state.Policy(nil))
	c.Assert(err, gc.IsNil)
	defer st.Close()
	attrs := map[string]interface{}{"type": "unknown"}
	err = st.UpdateEnvironConfig(attrs, nil, nil)
	c.Assert(err, gc.IsNil)
}

func (s *UpgradeSuite) openStateForUpgrade() (*state.State, func(), error) {
	mongoInfo := s.State.MongoConnectionInfo()
	st, err := state.Open(s.State.ModelTag(), mongoInfo, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if err != nil {
		return nil, nil, err
	}
	return st, func() { st.Close() }, nil
}

func (s *environSuite) TestEnvironmentChanges(c *gc.C) {
	originalConfig, err := s.State.EnvironConfig()
	c.Assert(err, gc.IsNil)

	logc := make(logChan, 1009)
	c.Assert(loggo.RegisterWriter("testing", logc, loggo.WARNING), gc.IsNil)
	defer loggo.RemoveWriter("testing")

	obs, err := worker.NewEnvironObserver(s.State)
	c.Assert(err, gc.IsNil)

	env := obs.Environ()
	c.Assert(env.Config().AllAttrs(), gc.DeepEquals, originalConfig.AllAttrs())
	var oldType string
	oldType = env.Config().AllAttrs()["type"].(string)

	info := s.MongoInfo(c)
	opts := mongo.DefaultDialOpts()
	st2, err := state.Open(info, opts, state.Policy(nil))
	defer st2.Close()

	// Change to an invalid configuration and check
	// that the observer's environment remains the same.
	st2.UpdateEnvironConfig(map[string]interface{}{"type": "invalid"}, nil, nil)
	st2.StartSync()

	// Wait for the observer to register the invalid environment
	timeout := time.After(coretesting.LongWait)
loop:
	for {
		select {
		case msg := <-logc:
			if strings.Contains(msg, "error creating Environ") {
				break loop
			}
		case <-timeout:
			c.Fatalf("timed out waiting to see broken environment")
		}
	}
	// Check that the returned environ is still the same.
	env = obs.Environ()
	c.Assert(env.Config().AllAttrs(), gc.DeepEquals, originalConfig.AllAttrs())

	// Change the environment back to a valid configuration
	// with a different name and check that we see it.
	st2.UpdateEnvironConfig(map[string]interface{}{"type": oldType, "name": "a-new-name"}, nil, nil)
	st2.StartSync()

	for a := coretesting.LongAttempt.Start(); a.Next(); {
		env := obs.Environ()
		if !a.HasNext() {
			c.Fatalf("timed out waiting for new environ")
		}
		if env.Config().Name() == "a-new-name" {
			break
		}
	}
}

func (s *AgentSuite) AssertCanOpenState(c *gc.C, tag names.Tag, dataDir string) {
	config, err := agent.ReadConfig(agent.ConfigPath(dataDir, tag))
	c.Assert(err, jc.ErrorIsNil)
	info, ok := config.MongoInfo()
	c.Assert(ok, jc.IsTrue)
	st, err := state.Open(config.Model(), info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, jc.ErrorIsNil)
	st.Close()
}

func (*NewConnSuite) TestConnWithPassword(c *gc.C) {
	attrs := dummy.SampleConfig().Merge(coretesting.Attrs{
		"admin-secret": "nutkin",
	})
	cfg, err := config.New(config.NoDefaults, attrs)
	c.Assert(err, gc.IsNil)
	ctx := coretesting.Context(c)
	env, err := environs.Prepare(cfg, ctx, configstore.NewMem())
	c.Assert(err, gc.IsNil)
	envtesting.UploadFakeTools(c, env.Storage())
	err = bootstrap.Bootstrap(ctx, env, environs.BootstrapParams{})
	c.Assert(err, gc.IsNil)

	// Check that Bootstrap has correctly used a hash
	// of the admin password.
	info, _, err := env.StateInfo()
	c.Assert(err, gc.IsNil)
	info.Password = utils.UserPasswordHash("nutkin", utils.CompatSalt)
	st, err := state.Open(info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, gc.IsNil)
	assertClose(c, st)

	// Check that we can connect with the original environment.
	conn, err := juju.NewConn(env)
	c.Assert(err, gc.IsNil)
	assertClose(c, conn)

	// Check that the password has now been changed to the original
	// admin password.
	info.Password = "nutkin"
	st1, err := state.Open(info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, gc.IsNil)
	assertClose(c, st1)

	// Check that we can still connect with the original
	// environment.
	conn, err = juju.NewConn(env)
	c.Assert(err, gc.IsNil)
	defer assertClose(c, conn)

	// Reset the admin password so the state db can be reused.
	err = conn.State.SetAdminMongoPassword("")
	c.Assert(err, gc.IsNil)
}

func (s *BootstrapSuite) TestInitializeEnvironment(c *gc.C) {
	hw := instance.MustParseHardware("arch=amd64 mem=8G")
	machConf, cmd, err := s.initBootstrapCommand(c, nil, "--env-config", s.envcfg, "--instance-id", string(s.instanceId), "--hardware", hw.String())
	c.Assert(err, gc.IsNil)
	err = cmd.Run(nil)
	c.Assert(err, gc.IsNil)

	c.Assert(s.fakeEnsureMongo.dataDir, gc.Equals, s.dataDir)
	c.Assert(s.fakeEnsureMongo.initiateCount, gc.Equals, 1)
	c.Assert(s.fakeEnsureMongo.ensureCount, gc.Equals, 1)
	c.Assert(s.fakeEnsureMongo.dataDir, gc.Equals, s.dataDir)
	c.Assert(s.fakeEnsureMongo.oplogSize, gc.Equals, 1234)

	expectInfo, exists := machConf.StateServingInfo()
	c.Assert(exists, jc.IsTrue)
	c.Assert(expectInfo.SharedSecret, gc.Equals, "")

	servingInfo := s.fakeEnsureMongo.info
	c.Assert(len(servingInfo.SharedSecret), gc.Not(gc.Equals), 0)
	servingInfo.SharedSecret = ""
	c.Assert(servingInfo, jc.DeepEquals, expectInfo)
	expectDialAddrs := []string{fmt.Sprintf("127.0.0.1:%d", expectInfo.StatePort)}
	gotDialAddrs := s.fakeEnsureMongo.initiateParams.DialInfo.Addrs
	c.Assert(gotDialAddrs, gc.DeepEquals, expectDialAddrs)

	memberHost := fmt.Sprintf("%s:%d", s.bootstrapName, expectInfo.StatePort)
	c.Assert(s.fakeEnsureMongo.initiateParams.MemberHostPort, gc.Equals, memberHost)
	c.Assert(s.fakeEnsureMongo.initiateParams.User, gc.Equals, "")
	c.Assert(s.fakeEnsureMongo.initiateParams.Password, gc.Equals, "")

	st, err := state.Open(&authentication.MongoInfo{
		Info: mongo.Info{
			Addrs:  []string{gitjujutesting.MgoServer.Addr()},
			CACert: testing.CACert,
		},
		Password: testPasswordHash(),
	}, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	c.Assert(err, gc.IsNil)
	defer st.Close()
	machines, err := st.AllMachines()
	c.Assert(err, gc.IsNil)
	c.Assert(machines, gc.HasLen, 1)

	instid, err := machines[0].InstanceId()
	c.Assert(err, gc.IsNil)
	c.Assert(instid, gc.Equals, instance.Id(string(s.instanceId)))

	stateHw, err := machines[0].HardwareCharacteristics()
	c.Assert(err, gc.IsNil)
	c.Assert(stateHw, gc.NotNil)
	c.Assert(*stateHw, gc.DeepEquals, hw)

	cons, err := st.EnvironConstraints()
	c.Assert(err, gc.IsNil)
	c.Assert(&cons, jc.Satisfies, constraints.IsEmpty)
}

func testOpenState(c *gc.C, info *authentication.MongoInfo, expectErrType error) {
	st, err := state.Open(info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if st != nil {
		st.Close()
	}
	if expectErrType != nil {
		c.Assert(err, gc.FitsTypeOf, expectErrType)
	} else {
		c.Assert(err, gc.IsNil)
	}
}

func testOpenState(c *gc.C, info *mongo.MongoInfo, expectErrType error) {
	st, err := state.Open(testing.EnvironmentTag, info, mongo.DefaultDialOpts(), environs.NewStatePolicy())
	if st != nil {
		st.Close()
	}
	if expectErrType != nil {
		c.Assert(err, gc.FitsTypeOf, expectErrType)
	} else {
		c.Assert(err, jc.ErrorIsNil)
	}
}