Merge lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir into lp:~landscape/fake-juju/trunk-old

[Eric Snow]

Add a FAKE_JUJU_DATA_DIR environment variable.

This change also does some clean-up. Note that the changes are almost
completely the same for the two Juju versions, so reviewing shouldn't
be as bad as the line-count might imply. If fake-juju had better code
re-use then this patch would be much smaller.

Add a FAKE_JUJU_DATA_DIR environment variable.

This change also does some clean-up. Note that the changes are almost
completely the same for the two Juju versions, so reviewing shouldn't
be as bad as the line-count might imply. If fake-juju had better code
re-use then this patch would be much smaller.

[🤖 Landscape Builder (landscape-builder)]

review: Abstain (executing tests)

[🤖 Landscape Builder (landscape-builder)]

Command: make ci-test
Result: Success
Revno: 53
Branch: lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir
Jenkins: https://ci.lscape.net/job/latch-test-xenial/310/

review: Approve (test results)

[lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir]

54. By Eric Snow on 2016-10-20

Merge from parent.

[🤖 Landscape Builder (landscape-builder)]

review: Abstain (executing tests)

[🤖 Landscape Builder (landscape-builder)]

Command: make ci-test
Result: Success
Revno: 54
Branch: lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir
Jenkins: https://ci.lscape.net/job/latch-test-xenial/313/

review: Approve (test results)

[Chad Smith (chad.smith)]

review: Approve

[Данило Шеган (danilo)]

Looks good, tests pass. +1

review: Approve

[lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir]

55. By Eric Snow on 2016-10-25

Clarify some names.

56. By Eric Snow on 2016-10-25

Add missing doc comments.

57. By Eric Snow on 2016-10-25

Clarify some names.

[🤖 Landscape Builder (landscape-builder)]

review: Abstain (executing tests)

[🤖 Landscape Builder (landscape-builder)]

Command: make ci-test
Result: Success
Revno: 57
Branch: lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir
Jenkins: https://ci.lscape.net/job/latch-test-xenial/332/

review: Approve (test results)

[lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir]

58. By Eric Snow on 2016-10-25

Merge from parent.

[🤖 Landscape Builder (landscape-builder)]

review: Abstain (executing tests)

[🤖 Landscape Builder (landscape-builder)]

Command: make ci-test
Result: Success
Revno: 58
Branch: lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir
Jenkins: https://ci.lscape.net/job/latch-test-xenial/333/

review: Approve (test results)

[lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir]

59. By Eric Snow on 2016-10-26

Merge from trunk.

[🤖 Landscape Builder (landscape-builder)]

review: Abstain (executing tests)

[🤖 Landscape Builder (landscape-builder)]

Command: make ci-test
Result: Success
Revno: 59
Branch: lp:~ericsnowcurrently/fake-juju/fake-juju-data-dir
Jenkins: https://ci.lscape.net/job/latch-test-xenial/346/

review: Approve (test results)

=== modified file '1.25.6/fake-juju.go'
--- 1.25.6/fake-juju.go	2016-10-18 16:35:29 +0000
+++ 1.25.6/fake-juju.go	2016-10-26 18:45:46 +0000
@@ -37,45 +37,42 @@
 )
 
 func main() {
+	code := 0
 	if len(os.Args) > 1 {
-		code := 0
 		err := handleCommand(os.Args[1])
 		if err != nil {
 			fmt.Println(err.Error())
 			code = 1
 		}
-		os.Exit(code)
+	} else {
+		// This kicks off the daemon.  See FakeJujuSuite below.
+		t := &testing.T{}
+		coretesting.MgoTestPackage(t)
 	}
-	t := &testing.T{}
-	coretesting.MgoTestPackage(t)
-}
-
-type processInfo struct {
-	Username     string
-	Password     string
-	WorkDir      string
-	EndpointAddr string
-	Uuid         string
-	CACert       string
+	os.Exit(code)
 }
 
 func handleCommand(command string) error {
+	filenames := newFakeJujuFilenames("", "", "")
 	if command == "bootstrap" {
-		return bootstrap()
+		return bootstrap(filenames)
 	}
 	if command == "api-endpoints" {
-		return apiEndpoints()
+		return apiEndpoints(filenames)
 	}
 	if command == "api-info" {
-		return apiInfo()
+		return apiInfo(filenames)
 	}
 	if command == "destroy-environment" {
-		return destroyEnvironment()
+		return destroyEnvironment(filenames)
 	}
 	return errors.New("command not found")
 }
 
-func bootstrap() error {
+func bootstrap(filenames fakejujuFilenames) error {
+	if err := filenames.ensureDirsExist(); err != nil {
+		return err
+	}
 	envName, config, err := environmentNameAndConfig()
 	if err != nil {
 		return err
@@ -91,10 +88,16 @@
 		return err
 	}
 	command.Start()
-	apiInfo, err := parseApiInfo(envName, stdout)
+
+	result, err := parseApiInfo(stdout)
 	if err != nil {
 		return err
 	}
+	if err := result.apply(filenames, envName); err != nil {
+		return err
+	}
+	apiInfo := result.apiInfo()
+
 	dialOpts := api.DialOpts{
 		DialAddressInterval: 50 * time.Millisecond,
 		Timeout:             5 * time.Second,
@@ -124,8 +127,8 @@
 	return errors.New("invalid delta")
 }
 
-func apiEndpoints() error {
-	info, err := readProcessInfo()
+func apiEndpoints(filenames fakejujuFilenames) error {
+	info, err := readProcessInfo(filenames)
 	if err != nil {
 		return err
 	}
@@ -133,8 +136,8 @@
 	return nil
 }
 
-func apiInfo() error {
-	info, err := readProcessInfo()
+func apiInfo(filenames fakejujuFilenames) error {
+	info, err := readProcessInfo(filenames)
 	if err != nil {
 		return err
 	}
@@ -143,13 +146,13 @@
 	return nil
 }
 
-func destroyEnvironment() error {
-	info, err := readProcessInfo()
+func destroyEnvironment(filenames fakejujuFilenames) error {
+	info, err := readProcessInfo(filenames)
 	if err != nil {
 		return err
 	}
-	fifoPath := filepath.Join(info.WorkDir, "fifo")
-	fd, err := os.OpenFile(fifoPath, os.O_APPEND|os.O_WRONLY, 0600)
+	filenames = newFakeJujuFilenames("", "", info.WorkDir)
+	fd, err := os.OpenFile(filenames.fifoFile(), os.O_APPEND|os.O_WRONLY, 0600)
 	if err != nil {
 		return err
 	}
@@ -177,94 +180,235 @@
 	return envName, config, nil
 }
 
-func parseApiInfo(envName string, stdout io.ReadCloser) (*api.Info, error) {
+// processInfo holds all the information that fake-juju uses internally.
+type processInfo struct {
+	Username     string
+	Password     string
+	WorkDir      string
+	EndpointAddr string
+	Uuid         string
+	CACert       []byte
+}
+
+func readProcessInfo(filenames fakejujuFilenames) (*processInfo, error) {
+	infoPath := filenames.infoFile()
+	data, err := ioutil.ReadFile(infoPath)
+	if err != nil {
+		return nil, err
+	}
+	info := &processInfo{}
+	err = goyaml.Unmarshal(data, info)
+	if err != nil {
+		return nil, err
+	}
+	return info, nil
+}
+
+func (info processInfo) write(infoPath string) error {
+	data, _ := goyaml.Marshal(&info)
+	if err := ioutil.WriteFile(infoPath, data, 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
+// fakejujuFilenames encapsulates the paths to all the directories and
+// files that are relevant to fake-juju.
+type fakejujuFilenames struct {
+	datadir string
+	logsdir string
+}
+
+func newFakeJujuFilenames(datadir, logsdir, jujucfgdir string) fakejujuFilenames {
+	if datadir == "" {
+		datadir = os.Getenv("FAKE_JUJU_DATA_DIR")
+		if datadir == "" {
+			if jujucfgdir == "" {
+				jujucfgdir = os.Getenv("JUJU_HOME")
+			}
+			datadir = jujucfgdir
+		}
+	}
+	if logsdir == "" {
+		logsdir = os.Getenv("FAKE_JUJU_LOGS_DIR")
+		if logsdir == "" {
+			logsdir = datadir
+		}
+	}
+	return fakejujuFilenames{datadir, logsdir}
+}
+
+func (fj fakejujuFilenames) ensureDirsExist() error {
+	if err := os.MkdirAll(fj.datadir, 0755); err != nil {
+		return err
+	}
+	if err := os.MkdirAll(fj.logsdir, 0755); err != nil {
+		return err
+	}
+	return nil
+}
+
+// infoFile() returns the path to the file that fake-juju uses as
+// its persistent storage for internal data.
+func (fj fakejujuFilenames) infoFile() string {
+	return filepath.Join(fj.datadir, "fakejuju")
+}
+
+// logsFile() returns the path to the file where fake-juju writes
+// its logs.  Note that the normal Juju logs are not written here.
+func (fj fakejujuFilenames) logsFile() string {
+	return filepath.Join(fj.logsdir, "fake-juju.log")
+}
+
+// fifoFile() returns the path to the FIFO file used by fake-juju.
+// The FIFO is used by the fake-juju subcommands to interact with
+// the daemon.
+func (fj fakejujuFilenames) fifoFile() string {
+	return filepath.Join(fj.datadir, "fifo")
+}
+
+// caCertFile() returns the path to the file holding the CA certificate
+// used by the Juju API server.  fake-juju writes the cert there as a
+// convenience for users.  It is not actually used for anything.
+func (fj fakejujuFilenames) caCertFile() string {
+	return filepath.Join(fj.datadir, "cert.ca")
+}
+
+// bootstrapResult encapsulates all significant information that came
+// from bootstrapping an environment.
+type bootstrapResult struct {
+	dummyEnvName string
+	cfgdir       string
+	uuid         string
+	username     string
+	password     string
+	addresses    []string
+	caCert       []byte
+}
+
+// apiInfo() composes the Juju API info corresponding to the result.
+func (br bootstrapResult) apiInfo() *api.Info {
+	return &api.Info{
+		Addrs:      br.addresses,
+		Tag:        names.NewLocalUserTag(br.username),
+		Password:   br.password,
+		CACert:     string(br.caCert),
+		EnvironTag: names.NewEnvironTag(br.uuid),
+	}
+}
+
+// fakeJujuInfo() composes, from the result, the set of information
+// that fake-juju should use internally.
+func (br bootstrapResult) fakeJujuInfo() *processInfo {
+	return &processInfo{
+		Username:     br.username,
+		Password:     br.password,
+		WorkDir:      br.cfgdir,
+		EndpointAddr: br.addresses[0],
+		Uuid:         br.uuid,
+		CACert:       br.caCert,
+	}
+}
+
+// logsSymlinkFilenames() determines the source and target paths for
+// a symlink to the fake-juju logs file.  Such a symlink is relevant
+// because the fake-juju daemon may not know where the log file is
+// meant to go. It defaults to putting the log file in the default Juju
+// config dir. In that case, a symlink should be created from there to
+// the user-defined Juju config dir ($JUJU_HOME).
+func (br bootstrapResult) logsSymlinkFilenames(targetLogsFile string) (source, target string) {
+	if os.Getenv("FAKE_JUJU_LOGS_DIR") != "" || os.Getenv("FAKE_JUJU_DATA_DIR") != "" {
+		return "", ""
+	}
+
+	filenames := newFakeJujuFilenames("", "", br.cfgdir)
+	source = filenames.logsFile()
+	target = targetLogsFile
+	return source, target
+}
+
+// jenvSymlinkFilenames() determines the source and target paths for
+// a symlink to the .jenv file for the identified environment.
+func (br bootstrapResult) jenvSymlinkFilenames(jujuHome, envName string) (source, target string) {
+	if jujuHome == "" || envName == "" {
+		return "", ""
+	}
+
+	source = filepath.Join(br.cfgdir, "environments", br.dummyEnvName+".jenv")
+	target = filepath.Join(jujuHome, "environments", envName+".jenv")
+	return source, target
+}
+
+// apply() writes out the information from the bootstrap result to the
+// various files identified by the provided filenames.
+func (br bootstrapResult) apply(filenames fakejujuFilenames, envName string) error {
+	if err := br.fakeJujuInfo().write(filenames.infoFile()); err != nil {
+		return err
+	}
+
+	logsSource, logsTarget := br.logsSymlinkFilenames(filenames.logsFile())
+	if logsSource != "" && logsTarget != "" {
+		if err := os.Symlink(logsSource, logsTarget); err != nil {
+			return err
+		}
+	}
+
+	jenvSource, jenvTarget := br.jenvSymlinkFilenames(os.Getenv("JUJU_HOME"), envName)
+	if jenvSource != "" && jenvTarget != "" {
+		if err := os.MkdirAll(filepath.Dir(jenvTarget), 0755); err != nil {
+			return err
+		}
+		if err := os.Symlink(jenvSource, jenvTarget); err != nil {
+			return err
+		}
+	}
+
+	if err := ioutil.WriteFile(filenames.caCertFile(), br.caCert, 0644); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// See github.com/juju/juju/blob/juju/testing/conn.go.
+const dummyEnvName = "dummyenv"
+
+func parseApiInfo(stdout io.ReadCloser) (*bootstrapResult, error) {
 	buffer := bufio.NewReader(stdout)
+
 	line, _, err := buffer.ReadLine()
 	if err != nil {
 		return nil, err
 	}
 	uuid := string(line)
-	environTag := names.NewEnvironTag(uuid)
+
 	line, _, err = buffer.ReadLine()
 	if err != nil {
 		return nil, err
 	}
 	workDir := string(line)
+
 	store, err := configstore.NewDisk(workDir)
 	if err != nil {
 		return nil, err
 	}
-	info, err := store.ReadInfo("dummyenv")
+	info, err := store.ReadInfo(dummyEnvName)
 	if err != nil {
 		return nil, err
 	}
+
 	credentials := info.APICredentials()
 	endpoint := info.APIEndpoint()
-	addresses := endpoint.Addresses
-	apiInfo := &api.Info{
-		Addrs:      addresses,
-		Tag:        names.NewLocalUserTag(credentials.User),
-		Password:   credentials.Password,
-		CACert:     endpoint.CACert,
-		EnvironTag: environTag,
-	}
-	err = writeProcessInfo(envName, &processInfo{
-		Username:     credentials.User,
-		Password:     credentials.Password,
-		WorkDir:      workDir,
-		EndpointAddr: addresses[0],
-		Uuid:         uuid,
-		CACert:       endpoint.CACert,
-	})
-	if err != nil {
-		return nil, err
-	}
-	return apiInfo, nil
-}
-
-func readProcessInfo() (*processInfo, error) {
-	infoPath := filepath.Join(os.Getenv("JUJU_HOME"), "fakejuju")
-	data, err := ioutil.ReadFile(infoPath)
-	if err != nil {
-		return nil, err
-	}
-	info := &processInfo{}
-	err = goyaml.Unmarshal(data, info)
-	if err != nil {
-		return nil, err
-	}
-	return info, nil
-}
-
-func writeProcessInfo(envName string, info *processInfo) error {
-	var err error
-	jujuHome := os.Getenv("JUJU_HOME")
-	infoPath := filepath.Join(jujuHome, "fakejuju")
-	logsDir := os.Getenv("FAKE_JUJU_LOGS_DIR")
-	if logsDir == "" {
-		logsDir = jujuHome
-	}
-	logPath := filepath.Join(logsDir, "fake-juju.log")
-	caCertPath := filepath.Join(jujuHome, "cert.ca")
-	envPath := filepath.Join(jujuHome, "environments")
-	os.Mkdir(envPath, 0755)
-	jEnvPath := filepath.Join(envPath, envName+".jenv")
-	data, _ := goyaml.Marshal(info)
-	if os.Getenv("FAKE_JUJU_LOGS_DIR") == "" {
-		err = os.Symlink(filepath.Join(info.WorkDir, "fake-juju.log"), logPath)
-		if err != nil {
-			return err
-		}
-	}
-	err = os.Symlink(filepath.Join(info.WorkDir, "environments/dummyenv.jenv"), jEnvPath)
-	if err != nil {
-		return err
-	}
-	err = ioutil.WriteFile(infoPath, data, 0644)
-	if err != nil {
-		return err
-	}
-	return ioutil.WriteFile(caCertPath, []byte(info.CACert), 0644)
+	result := &bootstrapResult{
+		dummyEnvName: dummyEnvName,
+		cfgdir:       workDir,
+		uuid:         uuid,
+		username:     credentials.User,
+		password:     credentials.Password,
+		addresses:    endpoint.Addresses,
+		caCert:       []byte(endpoint.CACert),
+	}
+	return result, nil
 }
 
 // Read the failures info file pointed by the FAKE_JUJU_FAILURES environment
@@ -304,12 +448,16 @@
 	return failuresInfo, nil
 }
 
+//===================================================================
+// The fake-juju daemon (started by bootstrap) is found here.  It is
+// implemented as a test suite.
+
 type FakeJujuSuite struct {
 	jujutesting.JujuConnSuite
 
 	instanceCount  int
 	machineStarted map[string]bool
-	fifoPath       string
+	filenames      fakejujuFilenames
 	logFile        *os.File
 }
 
@@ -376,15 +524,11 @@
 	c.Assert(err, gc.IsNil)
 	os.Setenv("PATH", binPath+":"+os.Getenv("PATH"))
 
-	s.fifoPath = filepath.Join(jujuHome, "fifo")
-	syscall.Mknod(s.fifoPath, syscall.S_IFIFO|0666, 0)
+	s.filenames = newFakeJujuFilenames("", "", jujuHome)
+	syscall.Mknod(s.filenames.fifoFile(), syscall.S_IFIFO|0666, 0)
 
 	// Logging
-	logsDir := os.Getenv("FAKE_JUJU_LOGS_DIR")
-	if logsDir == "" {
-		logsDir = jujuHome
-	}
-	logPath := filepath.Join(logsDir, "fake-juju.log")
+	logPath := s.filenames.logsFile()
 	s.logFile, err = os.OpenFile(logPath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
 	c.Assert(err, gc.IsNil)
 
@@ -404,16 +548,17 @@
 }
 
 func (s *FakeJujuSuite) TestStart(c *gc.C) {
+	fifoPath := s.filenames.fifoFile()
 	watcher := s.State.Watch()
 	go func() {
-		log.Println("Open commands FIFO", s.fifoPath)
-		fd, err := os.Open(s.fifoPath)
+		log.Println("Open commands FIFO", fifoPath)
+		fd, err := os.Open(fifoPath)
 		if err != nil {
 			log.Println("Failed to open commands FIFO")
 		}
 		c.Assert(err, gc.IsNil)
 		scanner := bufio.NewScanner(fd)
-		log.Println("Listen for commands on FIFO", s.fifoPath)
+		log.Println("Listen for commands on FIFO", fifoPath)
 		scanner.Scan()
 		log.Println("Stopping fake-juju")
 		watcher.Stop()
 
=== modified file '2.0-beta17/fake-juju.go'
--- 2.0-beta17/fake-juju.go	2016-09-15 19:05:50 +0000
+++ 2.0-beta17/fake-juju.go	2016-10-26 18:45:46 +0000
@@ -38,46 +38,46 @@
 )
 
 func main() {
+	code := 0
 	if len(os.Args) > 1 {
-		code := 0
 		err := handleCommand(os.Args[1])
 		if err != nil {
 			fmt.Println(err.Error())
 			code = 1
 		}
-		os.Exit(code)
+	} else {
+		// This kicks off the daemon.  See FakeJujuSuite below.
+		t := &testing.T{}
+		coretesting.MgoTestPackage(t)
 	}
-	t := &testing.T{}
-	coretesting.MgoTestPackage(t)
-}
-
-type processInfo struct {
-	WorkDir      string
-	EndpointAddr string
-	Uuid         string
-	CACert       string
+	os.Exit(code)
 }
 
 func handleCommand(command string) error {
+	filenames := newFakeJujuFilenames("", "", "")
 	if command == "bootstrap" {
-		return bootstrap()
+		return bootstrap(filenames)
 	}
 	if command == "show-controller" {
-		return apiInfo()
+		return apiInfo(filenames)
 	}
 	if command == "destroy-controller" {
-		return destroyEnvironment()
+		return destroyController(filenames)
 	}
 	return errors.New("command not found")
 }
 
-func bootstrap() error {
+func bootstrap(filenames fakejujuFilenames) error {
 	argc := len(os.Args)
 	if argc < 4 {
 		return errors.New(
 			"error: controller name and cloud name are required")
 	}
-	envName := os.Args[argc-2]
+	if err := filenames.ensureDirsExist(); err != nil {
+		return err
+	}
+	// XXX Swap the 2 args for juju-2.0-final.
+	controllerName := os.Args[argc-2]
 	command := exec.Command(os.Args[0])
 	command.Env = os.Environ()
 	command.Env = append(
@@ -89,10 +89,16 @@
 		return err
 	}
 	command.Start()
-	apiInfo, err := parseApiInfo(envName, stdout)
+
+	result, err := parseApiInfo(stdout)
 	if err != nil {
 		return err
 	}
+	if err := result.apply(filenames, controllerName); err != nil {
+		return err
+	}
+	apiInfo := result.apiInfo()
+
 	dialOpts := api.DialOpts{
 		DialAddressInterval: 50 * time.Millisecond,
 		Timeout:             5 * time.Second,
@@ -122,8 +128,8 @@
 	return errors.New("invalid delta")
 }
 
-func apiInfo() error {
-	info, err := readProcessInfo()
+func apiInfo(filenames fakejujuFilenames) error {
+	info, err := readProcessInfo(filenames)
 	if err != nil {
 		return err
 	}
@@ -140,13 +146,13 @@
 	return nil
 }
 
-func destroyEnvironment() error {
-	info, err := readProcessInfo()
+func destroyController(filenames fakejujuFilenames) error {
+	info, err := readProcessInfo(filenames)
 	if err != nil {
 		return err
 	}
-	fifoPath := filepath.Join(info.WorkDir, "fifo")
-	fd, err := os.OpenFile(fifoPath, os.O_APPEND|os.O_WRONLY, 0600)
+	filenames = newFakeJujuFilenames("", "", info.WorkDir)
+	fd, err := os.OpenFile(filenames.fifoFile(), os.O_APPEND|os.O_WRONLY, 0600)
 	if err != nil {
 		return err
 	}
@@ -158,13 +164,214 @@
 	return nil
 }
 
-func parseApiInfo(envName string, stdout io.ReadCloser) (*api.Info, error) {
+// processInfo holds all the information that fake-juju uses internally.
+type processInfo struct {
+	WorkDir      string
+	EndpointAddr string
+	Uuid         string
+	CACert       []byte
+}
+
+func readProcessInfo(filenames fakejujuFilenames) (*processInfo, error) {
+	infoPath := filenames.infoFile()
+	data, err := ioutil.ReadFile(infoPath)
+	if err != nil {
+		return nil, err
+	}
+	info := &processInfo{}
+	err = goyaml.Unmarshal(data, info)
+	if err != nil {
+		return nil, err
+	}
+	return info, nil
+}
+
+func (info processInfo) write(infoPath string) error {
+	data, _ := goyaml.Marshal(&info)
+	if err := ioutil.WriteFile(infoPath, data, 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
+// fakejujuFilenames encapsulates the paths to all the directories and
+// files that are relevant to fake-juju.
+type fakejujuFilenames struct {
+	datadir string
+	logsdir string
+}
+
+func newFakeJujuFilenames(datadir, logsdir, jujucfgdir string) fakejujuFilenames {
+	if datadir == "" {
+		datadir = os.Getenv("FAKE_JUJU_DATA_DIR")
+		if datadir == "" {
+			if jujucfgdir == "" {
+				jujucfgdir = os.Getenv("JUJU_DATA")
+			}
+			datadir = jujucfgdir
+		}
+	}
+	if logsdir == "" {
+		logsdir = os.Getenv("FAKE_JUJU_LOGS_DIR")
+		if logsdir == "" {
+			logsdir = datadir
+		}
+	}
+	return fakejujuFilenames{datadir, logsdir}
+}
+
+func (fj fakejujuFilenames) ensureDirsExist() error {
+	if err := os.MkdirAll(fj.datadir, 0755); err != nil {
+		return err
+	}
+	if err := os.MkdirAll(fj.logsdir, 0755); err != nil {
+		return err
+	}
+	return nil
+}
+
+// infoFile() returns the path to the file that fake-juju uses as
+// its persistent storage for internal data.
+func (fj fakejujuFilenames) infoFile() string {
+	return filepath.Join(fj.datadir, "fakejuju")
+}
+
+// logsFile() returns the path to the file where fake-juju writes
+// its logs.  Note that the normal Juju logs are not written here.
+func (fj fakejujuFilenames) logsFile() string {
+	return filepath.Join(fj.logsdir, "fake-juju.log")
+}
+
+// fifoFile() returns the path to the FIFO file used by fake-juju.
+// The FIFO is used by the fake-juju subcommands to interact with
+// the daemon.
+func (fj fakejujuFilenames) fifoFile() string {
+	return filepath.Join(fj.datadir, "fifo")
+}
+
+// caCertFile() returns the path to the file holding the CA certificate
+// used by the Juju API server.  fake-juju writes the cert there as a
+// convenience for users.  It is not actually used for anything.
+func (fj fakejujuFilenames) caCertFile() string {
+	return filepath.Join(fj.datadir, "cert.ca")
+}
+
+// bootstrapResult encapsulates all significant information that came
+// from bootstrapping a controller.
+type bootstrapResult struct {
+	dummyControllerName string
+	cfgdir              string
+	uuid                string
+	username            string
+	password            string
+	addresses           []string
+	caCert              []byte
+}
+
+// apiInfo() composes the Juju API info corresponding to the result.
+func (br bootstrapResult) apiInfo() *api.Info {
+	return &api.Info{
+		Addrs:    br.addresses,
+		Tag:      names.NewUserTag(br.username),
+		Password: br.password,
+		CACert:   string(br.caCert),
+		ModelTag: names.NewModelTag(br.uuid),
+	}
+}
+
+// fakeJujuInfo() composes, from the result, the set of information
+// that fake-juju should use internally.
+func (br bootstrapResult) fakeJujuInfo() *processInfo {
+	return &processInfo{
+		WorkDir:      br.cfgdir,
+		EndpointAddr: br.addresses[0],
+		Uuid:         br.uuid,
+		CACert:       br.caCert,
+	}
+}
+
+// logsSymlinkFilenames() determines the source and target paths for
+// a symlink to the fake-juju logs file.  Such a symlink is relevant
+// because the fake-juju daemon may not know where the log file is
+// meant to go. It defaults to putting the log file in the default Juju
+// config dir. In that case, a symlink should be created from there to
+// the user-defined Juju config dir ($JUJU_DATA).
+func (br bootstrapResult) logsSymlinkFilenames(targetLogsFile string) (source, target string) {
+	if os.Getenv("FAKE_JUJU_LOGS_DIR") != "" {
+		return "", ""
+	}
+
+	filenames := newFakeJujuFilenames("", "", br.cfgdir)
+	source = filenames.logsFile()
+	target = targetLogsFile
+	return source, target
+}
+
+// apply() writes out the information from the bootstrap result to the
+// various files identified by the provided filenames.
+func (br bootstrapResult) apply(filenames fakejujuFilenames, controllerName string) error {
+	if err := br.fakeJujuInfo().write(filenames.infoFile()); err != nil {
+		return err
+	}
+
+	logsSource, logsTarget := br.logsSymlinkFilenames(filenames.logsFile())
+	if logsSource != "" && logsTarget != "" {
+		if err := os.Symlink(logsSource, logsTarget); err != nil {
+			return err
+		}
+	}
+
+	if err := br.copyConfig(os.Getenv("JUJU_DATA"), controllerName); err != nil {
+		return err
+	}
+
+	if err := ioutil.WriteFile(filenames.caCertFile(), br.caCert, 0644); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (br bootstrapResult) copyConfig(targetCfgDir, controllerName string) error {
+	for _, name := range []string{"controllers.yaml", "models.yaml", "accounts.yaml"} {
+		source := filepath.Join(br.cfgdir, name)
+		target := filepath.Join(targetCfgDir, name)
+
+		input, err := ioutil.ReadFile(source)
+		if err != nil {
+			return err
+		}
+		// Generated configuration by test fixtures has the controller name
+		// hard-coded to "kontroll". A simple replace should fix this for
+		// clients using this config and expecting a specific controller
+		// name.
+		output := strings.Replace(string(input), dummyControllerName, controllerName, -1)
+		err = ioutil.WriteFile(target, []byte(output), 0644)
+		if err != nil {
+			return err
+		}
+	}
+
+	current := filepath.Join(targetCfgDir, "current-controller")
+	if err := ioutil.WriteFile(current, []byte(controllerName), 0644); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// See github.com/juju/juju/blob/juju/testing/conn.go.
+const dummyControllerName = "kontroll"
+
+func parseApiInfo(stdout io.ReadCloser) (*bootstrapResult, error) {
 	buffer := bufio.NewReader(stdout)
+
 	line, _, err := buffer.ReadLine()
 	if err != nil {
 		return nil, err
 	}
 	uuid := string(line)
+
 	line, _, err = buffer.ReadLine()
 	if err != nil {
 		return nil, err
@@ -175,8 +382,8 @@
 	store := jujuclient.NewFileClientStore()
 	// hard-coded value in juju testing
 	// This will be replaced in JUJU_DATA copy of the juju client config.
-	currentController := "kontroll"
-	one, err := store.ControllerByName("kontroll")
+	currentController := dummyControllerName
+	one, err := store.ControllerByName(currentController)
 	if err != nil {
 		return nil, err
 	}
@@ -185,108 +392,17 @@
 	if err != nil {
 		return nil, err
 	}
-	apiInfo := &api.Info{
-		Addrs:    one.APIEndpoints,
-		Tag:      names.NewUserTag(accountDetails.User),
-		Password: accountDetails.Password,
-		CACert:   one.CACert,
-		ModelTag: names.NewModelTag(uuid),
-	}
-
-	err = writeProcessInfo(envName, &processInfo{
-		WorkDir:      workDir,
-		EndpointAddr: one.APIEndpoints[0],
-		Uuid:         uuid,
-		CACert:       one.CACert,
-	})
-	if err != nil {
-		return nil, err
-	}
-	return apiInfo, nil
-}
-
-func readProcessInfo() (*processInfo, error) {
-	infoPath := filepath.Join(os.Getenv("JUJU_DATA"), "fakejuju")
-	data, err := ioutil.ReadFile(infoPath)
-	if err != nil {
-		return nil, err
-	}
-	info := &processInfo{}
-	err = goyaml.Unmarshal(data, info)
-	if err != nil {
-		return nil, err
-	}
-	return info, nil
-}
-
-func writeProcessInfo(envName string, info *processInfo) error {
-	var err error
-	jujuHome := os.Getenv("JUJU_DATA")
-	infoPath := filepath.Join(jujuHome, "fakejuju")
-	logsDir := os.Getenv("FAKE_JUJU_LOGS_DIR")
-	if logsDir == "" {
-		logsDir = jujuHome
-	}
-	logPath := filepath.Join(logsDir, "fake-juju.log")
-	caCertPath := filepath.Join(jujuHome, "cert.ca")
-	data, _ := goyaml.Marshal(info)
-	if os.Getenv("FAKE_JUJU_LOGS_DIR") == "" {
-		err = os.Symlink(filepath.Join(info.WorkDir, "fake-juju.log"), logPath)
-		if err != nil {
-			return err
-		}
-	}
-
-	err = copyClientConfig(
-		filepath.Join(info.WorkDir, "controllers.yaml"),
-		filepath.Join(jujuHome, "controllers.yaml"),
-		envName)
-	if err != nil {
-		return err
-	}
-	err = copyClientConfig(
-		filepath.Join(info.WorkDir, "models.yaml"),
-		filepath.Join(jujuHome, "models.yaml"),
-		envName)
-	if err != nil {
-		return err
-	}
-	err = copyClientConfig(
-		filepath.Join(info.WorkDir, "accounts.yaml"),
-		filepath.Join(jujuHome, "accounts.yaml"),
-		envName)
-	if err != nil {
-		return err
-	}
-	err = ioutil.WriteFile(
-		filepath.Join(jujuHome, "current-controller"),
-		[]byte(envName), 0644)
-	if err != nil {
-		return err
-	}
-
-	err = ioutil.WriteFile(infoPath, data, 0644)
-	if err != nil {
-		return err
-	}
-	return ioutil.WriteFile(caCertPath, []byte(info.CACert), 0644)
-}
-
-func copyClientConfig(src string, dst string, envName string) error {
-	input, err := ioutil.ReadFile(src)
-	if err != nil {
-		return err
-	}
-	// Generated configuration by test fixtures has the controller name
-	// hard-coded to "kontroll". A simple replace should fix this for
-	// clients using this config and expecting a specific controller
-	// name.
-	output := strings.Replace(string(input), "kontroll", envName, -1)
-	err = ioutil.WriteFile(dst, []byte(output), 0644)
-	if err != nil {
-		return err
-	}
-	return nil
+
+	result := &bootstrapResult{
+		dummyControllerName: dummyControllerName,
+		cfgdir:              workDir,
+		uuid:                uuid,
+		username:            accountDetails.User,
+		password:            accountDetails.Password,
+		addresses:           one.APIEndpoints,
+		caCert:              []byte(one.CACert),
+	}
+	return result, nil
 }
 
 // Read the failures info file pointed by the FAKE_JUJU_FAILURES environment
@@ -326,12 +442,16 @@
 	return failuresInfo, nil
 }
 
+//===================================================================
+// The fake-juju daemon (started by bootstrap) is found here.  It is
+// implemented as a test suite.
+
 type FakeJujuSuite struct {
 	jujutesting.JujuConnSuite
 
 	instanceCount  int
 	machineStarted map[string]bool
-	fifoPath       string
+	filenames      fakejujuFilenames
 	logFile        *os.File
 }
 
@@ -398,20 +518,16 @@
 	c.Assert(err, gc.IsNil)
 	os.Setenv("PATH", binPath+":"+os.Getenv("PATH"))
 
-	s.fifoPath = filepath.Join(jujuHome, "fifo")
-	syscall.Mknod(s.fifoPath, syscall.S_IFIFO|0666, 0)
+	s.filenames = newFakeJujuFilenames("", "", jujuHome)
+	syscall.Mknod(s.filenames.fifoFile(), syscall.S_IFIFO|0666, 0)
 
 	// Logging
-	logsDir := os.Getenv("FAKE_JUJU_LOGS_DIR")
-	if logsDir == "" {
-		logsDir = jujuHome
-	}
-	logPath := filepath.Join(logsDir, "fake-juju.log")
+	logPath := s.filenames.logsFile()
 	s.logFile, err = os.OpenFile(logPath, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
 	c.Assert(err, gc.IsNil)
 
 	log.SetOutput(s.logFile)
-	log.Println("Started fake-juju at", jujuHome)
+	log.Println("Started fake-juju at ", jujuHome)
 
 }
 
@@ -423,16 +539,17 @@
 }
 
 func (s *FakeJujuSuite) TestStart(c *gc.C) {
+	fifoPath := s.filenames.fifoFile()
 	watcher := s.State.Watch()
 	go func() {
-		log.Println("Open commands FIFO", s.fifoPath)
-		fd, err := os.Open(s.fifoPath)
+		log.Println("Open commands FIFO", fifoPath)
+		fd, err := os.Open(fifoPath)
 		if err != nil {
 			log.Println("Failed to open commands FIFO")
 		}
 		c.Assert(err, gc.IsNil)
 		scanner := bufio.NewScanner(fd)
-		log.Println("Listen for commands on FIFO", s.fifoPath)
+		log.Println("Listen for commands on FIFO", fifoPath)
 		scanner.Scan()
 		log.Println("Stopping fake-juju")
 		watcher.Stop()
 
=== modified file 'Makefile'
--- Makefile	2016-10-26 14:46:58 +0000
+++ Makefile	2016-10-26 18:45:46 +0000
@@ -14,7 +14,7 @@
 INSTALLDIR = $(DESTDIR)/usr/bin
 INSTALLED = $(INSTALLDIR)/fake-juju-$(JUJU_VERSION)
 
-$(JUJU_VERSION)/$(JUJU_VERSION):
+$(JUJU_VERSION)/$(JUJU_VERSION): $(JUJU_VERSION)/fake-juju.go
 	case $(JUJU_VERSION) in \
 		1.*) $(MAKE) build-common PATH=$$PATH JUJU_VERSION=$(JUJU_VERSION) ;;\
 		2.*) $(MAKE) build-common PATH=/usr/lib/go-$(GO_VERSION)/bin:$$PATH JUJU_VERSION=$(JUJU_VERSION) ;;\
 
=== modified file 'python/fakejuju/fakejuju.py'
--- python/fakejuju/fakejuju.py	2016-10-18 20:53:54 +0000
+++ python/fakejuju/fakejuju.py	2016-10-26 18:45:46 +0000
@@ -24,15 +24,17 @@
     return os.path.join(bindir, filename)
 
 
-def set_envvars(envvars, failures_filename=None, logsdir=None):
+def set_envvars(envvars, datadir=None, failures_filename=None, logsdir=None):
     """Return the environment variables with which to run fake-juju.
 
     @param envvars: The env dict to update.
+    @param datadir: The fake-juju data directory.
     @param failures_filename: The path to the failures file that
         fake-juju will use.
     @params logsdir: The path to the directory where fake-juju will
         write its log files.
     """
+    envvars["FAKE_JUJU_DATA_DIR"] = datadir or ""
     envvars["FAKE_JUJU_FAILURES"] = failures_filename or ""
     envvars["FAKE_JUJU_LOGS_DIR"] = logsdir or ""
 
@@ -41,46 +43,47 @@
     """The fundamental details for fake-juju."""
 
     @classmethod
-    def from_version(cls, version, cfgdir,
+    def from_version(cls, version, datadir,
                      logsdir=None, failuresdir=None, bindir=None):
         """Return a new instance given the provided information.
 
         @param version: The Juju version to fake.
-        @param cfgdir: The "juju home" directory to use.
+        @param datadir: The directory in which to store files specific
+            to fake-juju.
         @param logsdir: The directory where logs will be written.
-            This defaults to cfgdir.
+            This defaults to datadir.
         @params failuresdir: The directory where failure injection
             is managed.
         @param bindir: The directory containing the fake-juju binary.
             This defaults to /usr/bin.
         """
-        if logsdir is None:
-            logsdir = cfgdir
         if failuresdir is None:
-            failuresdir = cfgdir
+            failuresdir = datadir
         filename = get_filename(version, bindir=bindir)
         failures = Failures(failuresdir)
-        return cls(filename, version, cfgdir, logsdir, failures)
+        return cls(filename, version, datadir, logsdir, failures)
 
-    def __init__(self, filename, version, cfgdir, logsdir=None, failures=None):
+    def __init__(self, filename, version, datadir,
+                 logsdir=None, failures=None):
         """
         @param filename: The path to the fake-juju binary.
         @param version: The Juju version to fake.
-        @param cfgdir: The "juju home" directory to use.
+        @param datadir: The directory in which to store files specific
+            to fake-juju.
         @param logsdir: The directory where logs will be written.
-            This defaults to cfgdir.
+            This defaults to datadir.
         @param failures: The set of fake-juju failures to use.
         """
-        logsdir = logsdir if logsdir is not None else cfgdir
-        if failures is None and cfgdir:
-            failures = Failures(cfgdir)
+        logsdir = logsdir if logsdir is not None else datadir
+        if failures is None and datadir:
+            failures = Failures(datadir)
 
         if not filename:
             raise ValueError("missing filename")
         if not version:
             raise ValueError("missing version")
-        if not cfgdir:
-            raise ValueError("missing cfgdir")
+        if not datadir:
+            raise ValueError("missing datadir")
         if not logsdir:
             raise ValueError("missing logsdir")
         if failures is None:
@@ -88,7 +91,7 @@
 
         self.filename = filename
         self.version = version
-        self.cfgdir = cfgdir
+        self.datadir = datadir
         self.logsdir = logsdir
         self.failures = failures
 
@@ -100,19 +103,19 @@
     @property
     def infofile(self):
         """The path to fake-juju's data cache."""
-        return os.path.join(self.cfgdir, "fakejuju")
+        return os.path.join(self.datadir, "fakejuju")
 
     @property
     def fifo(self):
         """The path to the fifo file that triggers shutdown."""
-        return os.path.join(self.cfgdir, "fifo")
+        return os.path.join(self.datadir, "fifo")
 
     @property
     def cacertfile(self):
         """The path to the API server's certificate."""
-        return os.path.join(self.cfgdir, "cert.ca")
+        return os.path.join(self.datadir, "cert.ca")
 
-    def cli(self, envvars=None):
+    def cli(self, cfgdir, envvars=None):
         """Return the txjuju.cli.CLI for this fake-juju.
 
         Currently fake-juju supports only the following juju subcommands:
@@ -124,20 +127,23 @@
           Note that passwords are always omited, even if requested.
         * api-endpoints
         * destroy-environment
+
+        Note that fake-juju ignores local config files.
         """
         if envvars is None:
             envvars = os.environ
         envvars = dict(envvars)
-        set_envvars(envvars, self.failures._filename, self.logsdir)
+        set_envvars(
+            envvars, self.datadir, self.failures._filename, self.logsdir)
         return txjuju.cli.CLI.from_version(
-            self.filename, self.version, self.cfgdir, envvars)
+            self.filename, self.version, cfgdir, envvars)
 
-    def bootstrap(self, name, admin_secret=None):
+    def bootstrap(self, name, cfgdir, admin_secret=None):
         """Return the CLI and APIInfo after bootstrapping from scratch."""
         from . import get_bootstrap_spec
         spec = get_bootstrap_spec(name, admin_secret)
-        cfgfile = txjuju.prepare_for_bootstrap(spec, self.version, self.cfgdir)
-        cli = self.cli()
+        cfgfile = txjuju.prepare_for_bootstrap(spec, self.version, cfgdir)
+        cli = self.cli(cfgdir)
         cli.bootstrap(spec, cfgfile=cfgfile)
         api_info = cli.api_info(spec.name)
         return cli, api_info
 
=== modified file 'python/fakejuju/tests/test_fakejuju.py'
--- python/fakejuju/tests/test_fakejuju.py	2016-10-26 17:26:54 +0000
+++ python/fakejuju/tests/test_fakejuju.py	2016-10-26 18:45:46 +0000
@@ -50,9 +50,10 @@
     def test_all_args(self):
         """set_envvars() works correctly when given all args."""
         envvars = {}
-        set_envvars(envvars, "/spam/failures", "/eggs/logsdir")
+        set_envvars(envvars, "/spam", "/spam/failures", "/eggs/logsdir")
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "/spam",
             "FAKE_JUJU_FAILURES": "/spam/failures",
             "FAKE_JUJU_LOGS_DIR": "/eggs/logsdir",
             })
@@ -63,6 +64,7 @@
         set_envvars(envvars)
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "",
             "FAKE_JUJU_FAILURES": "",
             "FAKE_JUJU_LOGS_DIR": "",
             })
@@ -70,9 +72,10 @@
     def test_start_empty(self):
         """set_envvars() sets all values on an empty dict."""
         envvars = {}
-        set_envvars(envvars, "x", "y")
+        set_envvars(envvars, "w", "x", "y")
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "w",
             "FAKE_JUJU_FAILURES": "x",
             "FAKE_JUJU_LOGS_DIR": "y",
             })
@@ -80,10 +83,11 @@
     def test_no_collisions(self):
         """set_envvars() sets all values when none are set yet."""
         envvars = {"SPAM": "eggs"}
-        set_envvars(envvars, "x", "y")
+        set_envvars(envvars, "w", "x", "y")
 
         self.assertEqual(envvars, {
             "SPAM": "eggs",
+            "FAKE_JUJU_DATA_DIR": "w",
             "FAKE_JUJU_FAILURES": "x",
             "FAKE_JUJU_LOGS_DIR": "y",
             })
@@ -91,12 +95,14 @@
     def test_empty_to_nonempty(self):
         """set_envvars() updates empty values."""
         envvars = {
+            "FAKE_JUJU_DATA_DIR": "",
             "FAKE_JUJU_FAILURES": "",
             "FAKE_JUJU_LOGS_DIR": "",
             }
-        set_envvars(envvars, "x", "y")
+        set_envvars(envvars, "w", "x", "y")
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "w",
             "FAKE_JUJU_FAILURES": "x",
             "FAKE_JUJU_LOGS_DIR": "y",
             })
@@ -104,12 +110,14 @@
     def test_nonempty_to_nonempty(self):
         """set_envvars() overwrites existing values."""
         envvars = {
+            "FAKE_JUJU_DATA_DIR": "spam",
             "FAKE_JUJU_FAILURES": "spam",
             "FAKE_JUJU_LOGS_DIR": "ham",
             }
-        set_envvars(envvars, "x", "y")
+        set_envvars(envvars, "w", "x", "y")
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "w",
             "FAKE_JUJU_FAILURES": "x",
             "FAKE_JUJU_LOGS_DIR": "y",
             })
@@ -117,12 +125,14 @@
     def test_nonempty_to_empty(self):
         """set_envvars() with no args "unsets" existing values."""
         envvars = {
+            "FAKE_JUJU_DATA_DIR": "w",
             "FAKE_JUJU_FAILURES": "x",
             "FAKE_JUJU_LOGS_DIR": "y",
             }
         set_envvars(envvars)
 
         self.assertEqual(envvars, {
+            "FAKE_JUJU_DATA_DIR": "",
             "FAKE_JUJU_FAILURES": "",
             "FAKE_JUJU_LOGS_DIR": "",
             })
@@ -137,7 +147,7 @@
 
         self.assertEqual(juju.filename, "/bin/dir/fake-juju-1.25.6")
         self.assertEqual(juju.version, "1.25.6")
-        self.assertEqual(juju.cfgdir, "/a/juju/home")
+        self.assertEqual(juju.datadir, "/a/juju/home")
         self.assertEqual(juju.logsdir, "/logs/dir")
         self.assertEqual(juju.failures.filename, "/failures/dir/juju-failures")
 
@@ -147,19 +157,20 @@
 
         self.assertEqual(juju.filename, "/usr/bin/fake-juju-1.25.6")
         self.assertEqual(juju.version, "1.25.6")
-        self.assertEqual(juju.cfgdir, "/my/juju/home")
+        self.assertEqual(juju.datadir, "/my/juju/home")
         self.assertEqual(juju.logsdir, "/my/juju/home")
         self.assertEqual(juju.failures.filename, "/my/juju/home/juju-failures")
 
     def test_full(self):
         """FakeJuju() works correctly when given all args."""
-        cfgdir = "/my/juju/home"
-        failures = Failures(cfgdir)
-        juju = FakeJuju("/fake-juju", "1.25.6", cfgdir, "/some/logs", failures)
+        datadir = "/my/juju/home"
+        failures = Failures(datadir)
+        juju = FakeJuju(
+            "/fake-juju", "1.25.6", datadir, "/some/logs", failures)
 
         self.assertEqual(juju.filename, "/fake-juju")
         self.assertEqual(juju.version, "1.25.6")
-        self.assertEqual(juju.cfgdir, cfgdir)
+        self.assertEqual(juju.datadir, datadir)
         self.assertEqual(juju.logsdir, "/some/logs")
         self.assertIs(juju.failures, failures)
 
@@ -169,7 +180,7 @@
 
         self.assertEqual(juju.filename, "/fake-juju")
         self.assertEqual(juju.version, "1.25.6")
-        self.assertEqual(juju.cfgdir, "/my/juju/home")
+        self.assertEqual(juju.datadir, "/my/juju/home")
         self.assertEqual(juju.logsdir, "/my/juju/home")
         self.assertEqual(juju.failures.filename, "/my/juju/home/juju-failures")
 
@@ -180,7 +191,7 @@
         juju_unicode = FakeJuju(
             u"/fake-juju", u"1.25.6", u"/x", u"/y", Failures(u"/..."))
 
-        for name in ('filename version cfgdir logsdir'.split()):
+        for name in ('filename version datadir logsdir'.split()):
             self.assertIsInstance(getattr(juju_str, name), str)
             self.assertIsInstance(getattr(juju_unicode, name), unicode)
 
@@ -198,8 +209,8 @@
         with self.assertRaises(ValueError):
             FakeJuju("/fake-juju", "", "/my/juju/home")
 
-    def test_missing_cfgdir(self):
-        """FakeJuju() fails if cfgdir is None or empty."""
+    def test_missing_datadir(self):
+        """FakeJuju() fails if datadir is None or empty."""
         with self.assertRaises(ValueError):
             FakeJuju("/fake-juju", "1.25.6", None)
         with self.assertRaises(ValueError):
@@ -232,46 +243,48 @@
     def test_cli_full(self):
         """FakeJuju.cli() works correctly when given all args."""
         juju = FakeJuju("/fake-juju", "1.25.6", "/x")
-        cli = juju.cli({"SPAM": "eggs"})
+        cli = juju.cli("/y", {"SPAM": "eggs"})
 
         self.assertEqual(
             cli._exe,
             Executable("/fake-juju", {
                 "SPAM": "eggs",
+                "FAKE_JUJU_DATA_DIR": "/x",
                 "FAKE_JUJU_FAILURES": "/x/juju-failures",
                 "FAKE_JUJU_LOGS_DIR": "/x",
-                "JUJU_HOME": "/x",
+                "JUJU_HOME": "/y",
                 }),
             )
 
     def test_cli_minimal(self):
         """FakeJuju.cli() works correctly when given minimal args."""
         juju = FakeJuju("/fake-juju", "1.25.6", "/x")
-        cli = juju.cli()
+        cli = juju.cli("/y")
 
         self.assertEqual(
             cli._exe,
             Executable("/fake-juju", dict(os.environ, **{
+                "FAKE_JUJU_DATA_DIR": "/x",
                 "FAKE_JUJU_FAILURES": "/x/juju-failures",
                 "FAKE_JUJU_LOGS_DIR": "/x",
-                "JUJU_HOME": "/x",
+                "JUJU_HOME": "/y",
                 })),
             )
 
     def test_cli_juju1(self):
         """FakeJuju.cli() works correctly for Juju 1.x."""
         juju = FakeJuju.from_version("1.25.6", "/x")
-        cli = juju.cli()
+        cli = juju.cli("/y")
 
-        self.assertEqual(cli._exe.envvars["JUJU_HOME"], "/x")
+        self.assertEqual(cli._exe.envvars["JUJU_HOME"], "/y")
         self.assertIsInstance(cli._juju, _juju1.CLIHooks)
 
     def test_cli_juju2(self):
         """FakeJuju.cli() works correctly for Juju 2.x."""
         juju = FakeJuju.from_version("2.0.0", "/x")
-        cli = juju.cli()
+        cli = juju.cli("/y")
 
-        self.assertEqual(cli._exe.envvars["JUJU_DATA"], "/x")
+        self.assertEqual(cli._exe.envvars["JUJU_DATA"], "/y")
         self.assertIsInstance(cli._juju, _juju2.CLIHooks)
 
     def test_bootstrap(self):
@@ -283,21 +296,26 @@
                 model_uuid='deadbeef-0bad-400d-8000-4b1d0d06f00d',
                 )
         version = "1.25.6"
-        with tempdir() as datadir:
-            cfgdir = os.path.join(datadir, ".juju")
+        with tempdir() as testdir:
+            bindir = os.path.join(testdir, "bin")
+            datadir = os.path.join(testdir, "fakejuju")
+            cfgdir = os.path.join(testdir, ".juju")
 
             logfilename = write_fakejuju_script(
-                version, datadir, cfgdir, expected)
-            fakejuju = FakeJuju.from_version(version, cfgdir, bindir=datadir)
+                version, bindir, datadir, cfgdir, expected)
+            fakejuju = FakeJuju.from_version(version, cfgdir, bindir=bindir)
 
             # Make the calls.
-            cli, api_info = fakejuju.bootstrap("spam", "secret")
+            cli, api_info = fakejuju.bootstrap("spam", cfgdir, "secret")
             cli.destroy_controller()
 
             with open(logfilename) as logfile:
                 calls = [line.strip() for line in logfile]
-
-            files = os.listdir(cfgdir)
+            files = []
+            files.extend(os.path.join(os.path.basename(datadir), name)
+                         for name in os.listdir(datadir))
+            files.extend(os.path.join(os.path.basename(cfgdir), name)
+                         for name in os.listdir(cfgdir))
             with open(os.path.join(cfgdir, "environments.yaml")) as envfile:
                 data = envfile.read()
 
@@ -317,11 +335,12 @@
             "destroy-environment",
             ])
         self.assertItemsEqual(files, [
-            'cert.ca',
-            'environments',
-            'environments.yaml',
-            'fake-juju.log',
-            'fakejuju',
+            '.juju/environments',
+            '.juju/environments.yaml',
+            'fakejuju/cert.ca',
+            'fakejuju/fake-juju.log',
+            'fakejuju/fakejuju',
+            'fakejuju/fifo',
             ])
         self.assertEqual(yaml.load(data), {
             "environments": {
@@ -344,7 +363,10 @@
     logfile.write(" ".join(sys.argv) + "\\n")
 
 if sys.argv[1] == "bootstrap":
-    for filename in ("cert.ca", "environments", "fake-juju.log", "fakejuju"):
+    for filename in ("cert.ca", "fake-juju.log", "fakejuju", "fifo"):
+        with open(os.path.join("{datadir}", filename), "w"):
+            pass  # Touch the file.
+    for filename in ("environments",):
         with open(os.path.join("{cfgdir}", filename), "w"):
             pass  # Touch the file.
 elif sys.argv[1] in ("api-info", "show-controller"):
@@ -353,7 +375,7 @@
 """
 
 
-def write_fakejuju_script(version, bindir, cfgdir, api_info):
+def write_fakejuju_script(version, bindir, datadir, cfgdir, api_info):
     if version.startswith("1."):
         raw_api_info = {
             "state-servers": api_info.endpoints,
@@ -383,11 +405,14 @@
 
     logfile = os.path.join(bindir, "calls.log")
     script = FAKE_JUJU_SCRIPT.format(
-        cfgdir=cfgdir, logfile=logfile, output=output)
+        datadir=datadir, cfgdir=cfgdir, logfile=logfile, output=output)
     filename = get_filename(version, bindir)
+    os.makedirs(os.path.dirname(filename))
     with open(filename, "w") as scriptfile:
         scriptfile.write(script)
     os.chmod(filename, 0o755)
+    os.makedirs(datadir)
+
     return logfile