func TestPackage(t *testing.T) {
	// At this stage, Juju only supports running the apiservers and database
	// on Ubuntu. If we end up officially supporting CentOS, then we should
	// make sure we run the tests there.
	if os.HostOS() != os.Ubuntu {
		t.Skipf("skipping tests on %v", os.HostOS())
	}
	coretesting.MgoTestPackage(t)
}

// validateUploadAllowed returns an error if an attempt to upload tools should
// not be allowed.
func validateUploadAllowed(env environs.Environ, toolsArch, toolsSeries *string, validator constraints.Validator) error {
	// Now check that the architecture and series for which we are setting up an
	// environment matches that from which we are bootstrapping.
	hostArch := arch.HostArch()
	// We can't build tools for a different architecture if one is specified.
	if toolsArch != nil && *toolsArch != hostArch {
		return fmt.Errorf("cannot use agent built for %q using a machine running on %q", *toolsArch, hostArch)
	}
	hostOS := jujuos.HostOS()
	if toolsSeries != nil {
		toolsSeriesOS, err := series.GetOSFromSeries(*toolsSeries)
		if err != nil {
			return errors.Trace(err)
		}
		if !toolsSeriesOS.EquivalentTo(hostOS) {
			return errors.Errorf("cannot use agent built for %q using a machine running %q", *toolsSeries, hostOS)
		}
	}
	// If no architecture is specified, ensure the target provider supports instances matching our architecture.
	if _, err := validator.Validate(constraints.Value{Arch: &hostArch}); err != nil {
		return errors.Errorf(
			"model %q of type %s does not support instances running on %q",
			env.Config().Name(), env.Config().Type(), hostArch,
		)
	}
	return nil
}

// NewPaths returns the set of filesystem paths that the supplied unit should
// use, given the supplied root juju data directory path.
func NewPaths(dataDir string, unitTag names.UnitTag) Paths {

	join := filepath.Join
	baseDir := join(dataDir, "agents", unitTag.String())
	stateDir := join(baseDir, "state")

	socket := func(name string, abstract bool) string {
		if os.HostOS() == os.Windows {
			return fmt.Sprintf(`\\.\pipe\%s-%s`, unitTag, name)
		}
		path := join(baseDir, name+".socket")
		if abstract {
			path = "@" + path
		}
		return path
	}

	toolsDir := tools.ToolsDir(dataDir, unitTag.String())
	return Paths{
		ToolsDir: filepath.FromSlash(toolsDir),
		Runtime: RuntimePaths{
			JujuRunSocket:     socket("run", false),
			JujucServerSocket: socket("agent", true),
		},
		State: StatePaths{
			CharmDir:        join(baseDir, "charm"),
			OperationsFile:  join(stateDir, "uniter"),
			RelationsDir:    join(stateDir, "relations"),
			BundlesDir:      join(stateDir, "bundles"),
			DeployerDir:     join(stateDir, "deployer"),
			StorageDir:      join(stateDir, "storage"),
			MetricsSpoolDir: join(stateDir, "spool", "metrics"),
		},
	}
}

// NewWorker returns a worker that keeps track of
// the machine's authorised ssh keys and ensures the
// ~/.ssh/authorized_keys file is up to date.
func NewWorker(st *keyupdater.State, agentConfig agent.Config) worker.Worker {
	if os.HostOS() == os.Windows {
		return worker.NewNoOpWorker()
	}
	kw := &keyupdaterWorker{st: st, tag: agentConfig.Tag().(names.MachineTag)}
	return worker.NewNotifyWorker(kw)
}

func (runner *runner) runCharmHookWithLocation(hookName, charmLocation string) error {
	srv, err := runner.startJujucServer()
	if err != nil {
		return err
	}
	defer srv.Close()

	env, err := runner.context.HookVars(runner.paths)
	if err != nil {
		return errors.Trace(err)
	}
	if jujuos.HostOS() == jujuos.Windows {
		// TODO(fwereade): somehow consolidate with utils/exec?
		// We don't do this on the other code path, which uses exec.RunCommands,
		// because that already has handling for windows environment requirements.
		env = mergeWindowsEnvironment(env, os.Environ())
	}

	debugctx := debug.NewHooksContext(runner.context.UnitName())
	if session, _ := debugctx.FindSession(); session != nil && session.MatchHook(hookName) {
		logger.Infof("executing %s via debug-hooks", hookName)
		err = session.RunHook(hookName, runner.paths.GetCharmDir(), env)
	} else {
		err = runner.runCharmHook(hookName, env, charmLocation)
	}
	return runner.context.Flush(hookName, err)
}

func syslogUserGroup() (string, string) {
	switch os.HostOS() {
	case os.CentOS:
		return "root", "adm"
	default:
		return "syslog", "syslog"
	}
}

func syslogUser() string {
	switch jujuos.HostOS() {
	case jujuos.CentOS:
		return "root"
	default:
		return "syslog"
	}
}

// appendProxyToCommands activates proxy settings on platforms
// that support this feature via the command line. Currently this
// will work on most GNU/Linux systems, but has no use in Windows
// where the proxy settings are taken from the registry or from
// application specific settings (proxy settings in firefox ignore
// registry values on Windows).
func (c *RunCommand) appendProxyToCommands() string {
	switch jujuos.HostOS() {
	case jujuos.Ubuntu:
		return `[ -f "/home/ubuntu/.juju-proxy" ] && . "/home/ubuntu/.juju-proxy"` + "\n" + c.commands
	default:
		return c.commands
	}
}

func (w *proxyWorker) writeEnvironment() error {
	switch os.HostOS() {
	case os.Windows:
		return w.writeEnvironmentToRegistry()
	default:
		return w.writeEnvironmentFile()
	}
}

// OSDependentEnvVars returns the OS-dependent environment variables that
// should be set for a hook context.
func OSDependentEnvVars(paths Paths) []string {
	switch jujuos.HostOS() {
	case jujuos.Windows:
		return windowsEnv(paths)
	case jujuos.Ubuntu:
		return ubuntuEnv(paths)
	case jujuos.CentOS:
		return centosEnv(paths)
	}
	return nil
}

// removeJujudpass removes a file that is no longer used on versions >1.25
// The Jujud.pass file was created during cloud init before
// so we know it's location for sure in case it exists
func removeJujudpass(context Context) error {
	if os.HostOS() == os.Windows {
		fileLocation := "C:\\Juju\\Jujud.pass"
		if err := osRemove(fileLocation); err != nil {
			// Don't fail the step if we can't get rid of the old files.
			// We don't actually care if they still exist or not.
			logger.Warningf("can't delete old password file %q: %s", fileLocation, err)
		}
	}
	return nil
}

// newRsyslogConfigWorker returns a worker.Worker that uses
// WatchForRsyslogChanges and updates rsyslog configuration based
// on changes. The worker will remove the configuration file
// on teardown.
func newRsyslogConfigWorker(st *apirsyslog.State, mode RsyslogMode, tag names.Tag, namespace string, stateServerAddrs []string, jujuConfigDir string) (worker.Worker, error) {
	if jujuos.HostOS() == jujuos.Windows && mode == RsyslogModeAccumulate {
		return worker.NewNoOpWorker(), nil
	}
	handler, err := newRsyslogConfigHandler(st, mode, tag, namespace, stateServerAddrs, jujuConfigDir)
	if err != nil {
		return nil, err
	}
	logger.Debugf("starting rsyslog worker mode %v for %q %q", mode, tag, namespace)
	return worker.NewNotifyWorker(handler), nil
}

func (s *supportedSeriesSuite) TestSeriesVersion(c *gc.C) {
	// There is no distro-info on Windows or CentOS.
	if os.HostOS() != os.Ubuntu {
		c.Skip("This test is only relevant on Ubuntu.")
	}
	vers, err := series.SeriesVersion("precise")
	if err != nil && err.Error() == `invalid series "precise"` {
		c.Fatalf(`Unable to lookup series "precise", you may need to: apt-get install distro-info`)
	}
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(vers, gc.Equals, "12.04")
}

// addJujuRegKey tries to create the same key that is now created during cloudinit
// on machines having version 1.25 or up
// Since support for ACL's in golang is quite disastrous at the moment, and they're
// not especially easy to use, this is done using the exact same steps used in cloudinit
func addJujuRegKey(context Context) error {
	if os.HostOS() == os.Windows {
		cmds := cloudconfig.CreateJujuRegistryKeyCmds()
		_, err := execRunCommands(exec.RunParams{
			Commands: strings.Join(cmds, "\n"),
		})
		if err != nil {
			return errors.Annotate(err, "could not create juju registry key")
		}
		logger.Infof("created juju registry key at %s", osenv.JujuRegistryKey)
		return nil
	}
	return nil
}

// locallyBuildableTools returns the list of tools that
// can be built locally, for series of the same OS.
func locallyBuildableTools() (buildable coretools.List) {
	for _, ser := range series.SupportedSeries() {
		if os, err := series.GetOSFromSeries(ser); err != nil || os != jujuos.HostOS() {
			continue
		}
		binary := version.Binary{
			Number: version.Current.Number,
			Series: ser,
			Arch:   arch.HostArch(),
		}
		// Increment the build number so we know it's a development build.
		binary.Build++
		buildable = append(buildable, &coretools.Tools{Version: binary})
	}
	return buildable
}

func GetPackageManager() (s PackageManagerStruct, err error) {
	switch jujuos.HostOS() {
	case jujuos.CentOS:
		s.PackageManager = "yum"
		s.PackageQuery = "yum"
		s.RepositoryManager = "yum-config-manager --add-repo"
	case jujuos.Ubuntu:
		s.PackageManager = "apt-get"
		s.PackageQuery = "dpkg-query"
		s.RepositoryManager = "add-apt-repository"
	default:
		s.PackageManager = "apt-get"
		s.PackageQuery = "dpkg-query"
		s.RepositoryManager = "add-apt-repository"
	}
	return s, nil
}

// hookCommand constructs an appropriate command to be passed to
// exec.Command(). The exec package uses cmd.exe as default on windows.
// cmd.exe does not know how to execute ps1 files by default, and
// powershell needs a few flags to allow execution (-ExecutionPolicy)
// and propagate error levels (-File). .cmd and .bat files can be run
// directly.
func hookCommand(hook string) []string {
	if jujuos.HostOS() != jujuos.Windows {
		// we are not running on windows,
		// just return the hook name
		return []string{hook}
	}
	if strings.HasSuffix(hook, ".ps1") {
		return []string{
			"powershell.exe",
			"-NonInteractive",
			"-ExecutionPolicy",
			"RemoteSigned",
			"-File",
			hook,
		}
	}
	return []string{hook}
}

func (s *RunTestSuite) runListenerForAgent(c *gc.C, agent string) {
	agentDir := filepath.Join(cmdutil.DataDir, "agents", agent)
	err := os.MkdirAll(agentDir, 0755)
	c.Assert(err, jc.ErrorIsNil)
	var socketPath string
	switch jujuos.HostOS() {
	case jujuos.Windows:
		socketPath = fmt.Sprintf(`\\.\pipe\%s-run`, agent)
	default:
		socketPath = fmt.Sprintf("%s/run.socket", agentDir)
	}
	listener, err := uniter.NewRunListener(&mockRunner{c}, socketPath)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(listener, gc.NotNil)
	s.AddCleanup(func(*gc.C) {
		c.Assert(listener.Close(), jc.ErrorIsNil)
	})
}

// NewWorker returns a worker that keeps track of
// the machine's authorised ssh keys and ensures the
// ~/.ssh/authorized_keys file is up to date.
func NewWorker(st *keyupdater.State, agentConfig agent.Config) (worker.Worker, error) {
	machineTag, ok := agentConfig.Tag().(names.MachineTag)
	if !ok {
		return nil, errors.NotValidf("machine tag %v", agentConfig.Tag())
	}
	if os.HostOS() == os.Windows {
		return worker.NewNoOpWorker(), nil
	}
	w, err := watcher.NewNotifyWorker(watcher.NotifyConfig{
		Handler: &keyupdaterWorker{
			st:  st,
			tag: machineTag,
		},
	})
	if err != nil {
		return nil, errors.Trace(err)
	}
	return w, nil
}

// locallyBuildableTools returns the list of tools that
// can be built locally, for series of the same OS.
func locallyBuildableTools(toolsSeries *string) (buildable coretools.List, _ version.Number) {
	buildNumber := jujuversion.Current
	// Increment the build number so we know it's a custom build.
	buildNumber.Build++
	for _, ser := range series.SupportedSeries() {
		if os, err := series.GetOSFromSeries(ser); err != nil || !os.EquivalentTo(jujuos.HostOS()) {
			continue
		}
		if toolsSeries != nil && ser != *toolsSeries {
			continue
		}
		binary := version.Binary{
			Number: buildNumber,
			Series: ser,
			Arch:   arch.HostArch(),
		}
		buildable = append(buildable, &coretools.Tools{Version: binary})
	}
	return buildable, buildNumber
}