func (s *SSHSuite) testSSHCommandHostAddressRetry(c *gc.C, proxy bool) {
	m := s.makeMachines(1, c, false)
	ctx := coretesting.Context(c)

	var called int
	next := func() bool {
		called++
		return called < 2
	}
	attemptStarter := &callbackAttemptStarter{next: next}
	s.PatchValue(&sshHostFromTargetAttemptStrategy, attemptStarter)

	// Ensure that the ssh command waits for a public address, or the attempt
	// strategy's Done method returns false.
	args := []string{"--proxy=" + fmt.Sprint(proxy), "0"}
	code := cmd.Main(&SSHCommand{}, ctx, args)
	c.Check(code, gc.Equals, 1)
	c.Assert(called, gc.Equals, 2)
	called = 0
	attemptStarter.next = func() bool {
		called++
		if called > 1 {
			s.setAddresses(m[0], c)
		}
		return true
	}
	code = cmd.Main(&SSHCommand{}, ctx, args)
	c.Check(code, gc.Equals, 0)
	c.Assert(called, gc.Equals, 2)
}

// Main runs the Command specified by req, and fills in resp. A single command
// is run at a time.
func (j *Jujuc) Main(req Request, resp *exec.ExecResponse) error {
	if req.CommandName == "" {
		return badReqErrorf("command not specified")
	}
	if !filepath.IsAbs(req.Dir) {
		return badReqErrorf("Dir is not absolute")
	}
	c, err := j.getCmd(req.ContextId, req.CommandName)
	if err != nil {
		return badReqErrorf("%s", err)
	}
	var stdin, stdout, stderr bytes.Buffer
	ctx := &cmd.Context{
		Dir:    req.Dir,
		Stdin:  &stdin,
		Stdout: &stdout,
		Stderr: &stderr,
	}
	j.mu.Lock()
	defer j.mu.Unlock()
	logger.Infof("running hook tool %q %q", req.CommandName, req.Args)
	logger.Debugf("hook context id %q; dir %q", req.ContextId, req.Dir)
	resp.Code = cmd.Main(c, ctx, req.Args)
	resp.Stdout = stdout.Bytes()
	resp.Stderr = stderr.Bytes()
	return nil
}

func (s *RelationListSuite) TestRelationList(c *gc.C) {
	for i, t := range relationListTests {
		c.Logf("test %d: %s", i, t.summary)
		hctx := s.GetHookContext(c, t.relid, "")
		setMembers(hctx.rels[0], t.members0)
		setMembers(hctx.rels[1], t.members1)
		com, err := jujuc.NewCommand(hctx, "relation-list")
		c.Assert(err, gc.IsNil)
		ctx := testing.Context(c)
		code := cmd.Main(com, ctx, t.args)
		c.Logf(bufferString(ctx.Stderr))
		c.Assert(code, gc.Equals, t.code)
		if code == 0 {
			c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
			expect := t.out
			if expect != "" {
				expect = expect + "\n"
			}
			c.Assert(bufferString(ctx.Stdout), gc.Equals, expect)
		} else {
			c.Assert(bufferString(ctx.Stdout), gc.Equals, "")
			expect := fmt.Sprintf(`(.|\n)*error: %s\n`, t.out)
			c.Assert(bufferString(ctx.Stderr), gc.Matches, expect)
		}
	}
}

func (s *RelationIdsSuite) TestHelp(c *gc.C) {
	template := `
usage: %s
purpose: list all relation ids with the given relation name

options:
--format  (= smart)
    specify output format (json|smart|yaml)
-o, --output (= "")
    specify an output file
%s`[1:]

	for relid, t := range map[int]struct {
		usage, doc string
	}{
		-1: {"relation-ids [options] <name>", ""},
		0:  {"relation-ids [options] [<name>]", "\nCurrent default relation name is \"x\".\n"},
		3:  {"relation-ids [options] [<name>]", "\nCurrent default relation name is \"y\".\n"},
	} {
		c.Logf("relid %d", relid)
		hctx := s.GetHookContext(c, relid, "")
		com, err := jujuc.NewCommand(hctx, "relation-ids")
		c.Assert(err, gc.IsNil)
		ctx := testing.Context(c)
		code := cmd.Main(com, ctx, []string{"--help"})
		c.Assert(code, gc.Equals, 0)
		expect := fmt.Sprintf(template, t.usage, t.doc)
		c.Assert(bufferString(ctx.Stdout), gc.Equals, expect)
		c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
	}
}

func (s *RelationListSuite) TestRelationListHelp(c *gc.C) {
	template := `
usage: relation-list [options]
purpose: list relation units

options:
--format  (= smart)
    specify output format (json|smart|yaml)
-o, --output (= "")
    specify an output file
-r  (= %s)
    specify a relation by id
%s`[1:]

	for relid, t := range map[int]struct {
		usage, doc string
	}{
		-1: {"", "\n-r must be specified when not in a relation hook\n"},
		0:  {"peer0:0", ""},
	} {
		c.Logf("test relid %d", relid)
		hctx := s.GetHookContext(c, relid, "")
		com, err := jujuc.NewCommand(hctx, "relation-list")
		c.Assert(err, gc.IsNil)
		ctx := testing.Context(c)
		code := cmd.Main(com, ctx, []string{"--help"})
		c.Assert(code, gc.Equals, 0)
		expect := fmt.Sprintf(template, t.usage, t.doc)
		c.Assert(bufferString(ctx.Stdout), gc.Equals, expect)
		c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
	}
}

// Main registers subcommands for the juju-metadata executable, and hands over control
// to the cmd package. This function is not redundant with main, because it
// provides an entry point for testing with arbitrary command line arguments.
func Main(args []string) {
	ctx, err := cmd.DefaultContext()
	if err != nil {
		fmt.Fprintf(os.Stderr, "error: %v\n", err)
		os.Exit(2)
	}
	if err := juju.InitJujuHome(); err != nil {
		fmt.Fprintf(os.Stderr, "error: %s\n", err)
		os.Exit(2)
	}
	metadatacmd := cmd.NewSuperCommand(cmd.SuperCommandParams{
		Name:        "metadata",
		UsagePrefix: "juju",
		Doc:         metadataDoc,
		Purpose:     "tools for generating and validating image and tools metadata",
		Log:         &cmd.Log{}})

	metadatacmd.Register(&ValidateImageMetadataCommand{})
	metadatacmd.Register(&ImageMetadataCommand{})
	metadatacmd.Register(&ToolsMetadataCommand{})
	metadatacmd.Register(&ValidateToolsMetadataCommand{})
	metadatacmd.Register(&SignMetadataCommand{})

	os.Exit(cmd.Main(metadatacmd, ctx, args[1:]))
}

func (s *CmdSuite) TestUnknownOutputFormat(c *gc.C) {
	ctx := testing.Context(c)
	result := cmd.Main(&OutputCommand{}, ctx, []string{"--format", "cuneiform"})
	c.Check(result, gc.Equals, 2)
	c.Check(bufferString(ctx.Stdout), gc.Equals, "")
	c.Check(bufferString(ctx.Stderr), gc.Matches, ".*: unknown format \"cuneiform\"\n")
}

func (s *CmdSuite) TestMainSuccess(c *gc.C) {
	ctx := testing.Context(c)
	result := cmd.Main(&TestCommand{Name: "verb"}, ctx, []string{"--option", "success!"})
	c.Assert(result, gc.Equals, 0)
	c.Assert(bufferString(ctx.Stdout), gc.Equals, "success!\n")
	c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
}

func (s *CmdSuite) TestMainRunSilentError(c *gc.C) {
	ctx := testing.Context(c)
	result := cmd.Main(&TestCommand{Name: "verb"}, ctx, []string{"--option", "silent-error"})
	c.Assert(result, gc.Equals, 1)
	c.Assert(bufferString(ctx.Stdout), gc.Equals, "")
	c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
}

func (s *GetSuite) TestGetConfig(c *gc.C) {
	sch := s.AddTestingCharm(c, "dummy")
	svc := s.AddTestingService(c, "dummy-service", sch)
	err := svc.UpdateConfigSettings(charm.Settings{"title": "Nearly There"})
	c.Assert(err, gc.IsNil)
	for _, t := range getTests {
		ctx := coretesting.Context(c)
		code := cmd.Main(&GetCommand{}, ctx, []string{t.service})
		c.Check(code, gc.Equals, 0)
		c.Assert(ctx.Stderr.(*bytes.Buffer).String(), gc.Equals, "")
		// round trip via goyaml to avoid being sucked into a quagmire of
		// map[interface{}]interface{} vs map[string]interface{}. This is
		// also required if we add json support to this command.
		buf, err := goyaml.Marshal(t.expected)
		c.Assert(err, gc.IsNil)
		expected := make(map[string]interface{})
		err = goyaml.Unmarshal(buf, &expected)
		c.Assert(err, gc.IsNil)

		actual := make(map[string]interface{})
		err = goyaml.Unmarshal(ctx.Stdout.(*bytes.Buffer).Bytes(), &actual)
		c.Assert(err, gc.IsNil)
		c.Assert(actual, gc.DeepEquals, expected)
	}
}

func (s *SSHSuite) TestSSHCommand(c *gc.C) {
	m := s.makeMachines(3, c, true)
	ch := coretesting.Charms.Dir("dummy")
	curl := charm.MustParseURL(
		fmt.Sprintf("local:quantal/%s-%d", ch.Meta().Name, ch.Revision()),
	)
	bundleURL, err := url.Parse("http://bundles.testing.invalid/dummy-1")
	c.Assert(err, gc.IsNil)
	dummy, err := s.State.AddCharm(ch, curl, bundleURL, "dummy-1-sha256")
	c.Assert(err, gc.IsNil)
	srv := s.AddTestingService(c, "mysql", dummy)
	s.addUnit(srv, m[0], c)

	srv = s.AddTestingService(c, "mongodb", dummy)
	s.addUnit(srv, m[1], c)
	s.addUnit(srv, m[2], c)

	for i, t := range sshTests {
		c.Logf("test %d: %s -> %s\n", i, t.about, t.args)
		ctx := coretesting.Context(c)
		jujucmd := cmd.NewSuperCommand(cmd.SuperCommandParams{})
		jujucmd.Register(&SSHCommand{})

		code := cmd.Main(jujucmd, ctx, t.args)
		c.Check(code, gc.Equals, 0)
		c.Check(ctx.Stderr.(*bytes.Buffer).String(), gc.Equals, "")
		c.Check(ctx.Stdout.(*bytes.Buffer).String(), gc.Equals, t.result)
	}
}

func runCmdLine(c *gc.C, com cmd.Command, args ...string) (code int, stdout, stderr string) {
	ctx := coretesting.Context(c)
	code = cmd.Main(com, ctx, args)
	stdout = ctx.Stdout.(*bytes.Buffer).String()
	stderr = ctx.Stderr.(*bytes.Buffer).String()
	c.Logf("args:   %#v\ncode:   %d\nstdout: %q\nstderr: %q", args, code, stdout, stderr)
	return
}

func (s *SuperCommandSuite) TestDescription(c *gc.C) {
	jc := cmd.NewSuperCommand(cmd.SuperCommandParams{Name: "jujutest", Purpose: "blow up the death star"})
	jc.Register(&TestCommand{Name: "blah"})
	ctx := testing.Context(c)
	code := cmd.Main(jc, ctx, []string{"blah", "--description"})
	c.Assert(code, gc.Equals, 0)
	c.Assert(bufferString(ctx.Stdout), gc.Equals, "blow up the death star\n")
}

// assertSetSuccess sets configuration options and checks the expected settings.
func assertSetSuccess(c *gc.C, dir string, svc *state.Service, args []string, expect charm.Settings) {
	ctx := coretesting.ContextForDir(c, dir)
	code := cmd.Main(&SetCommand{}, ctx, append([]string{"dummy-service"}, args...))
	c.Check(code, gc.Equals, 0)
	settings, err := svc.ConfigSettings()
	c.Assert(err, gc.IsNil)
	c.Assert(settings, gc.DeepEquals, expect)
}

func (s *ConfigGetSuite) TestAllPlusKey(c *gc.C) {
	hctx := s.GetHookContext(c, -1, "")
	com, err := jujuc.NewCommand(hctx, "config-get")
	c.Assert(err, gc.IsNil)
	ctx := testing.Context(c)
	code := cmd.Main(com, ctx, []string{"--all", "--format", "json", "monsters"})
	c.Assert(code, gc.Equals, 2)
	c.Assert(bufferString(ctx.Stderr), gc.Equals, "error: cannot use argument --all together with key \"monsters\"\n")
}

func (s *CmdSuite) TestMainHelp(c *gc.C) {
	for _, arg := range []string{"-h", "--help"} {
		ctx := testing.Context(c)
		result := cmd.Main(&TestCommand{Name: "verb"}, ctx, []string{arg})
		c.Assert(result, gc.Equals, 0)
		c.Assert(bufferString(ctx.Stdout), gc.Equals, fullHelp)
		c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
	}
}

func (s *ToolsMetadataSuite) TestNoTools(c *gc.C) {
	ctx := coretesting.Context(c)
	code := cmd.Main(&ToolsMetadataCommand{}, ctx, nil)
	c.Assert(code, gc.Equals, 1)
	stdout := ctx.Stdout.(*bytes.Buffer).String()
	c.Assert(stdout, gc.Matches, "Finding tools in .*\n")
	stderr := ctx.Stderr.(*bytes.Buffer).String()
	c.Assert(stderr, gc.Matches, "error: no tools available\n")
}

func (s *CmdSuite) TestStdin(c *gc.C) {
	const phrase = "Do you, Juju?"
	ctx := testing.Context(c)
	ctx.Stdin = bytes.NewBuffer([]byte(phrase))
	result := cmd.Main(&TestCommand{Name: "verb"}, ctx, []string{"--option", "echo"})
	c.Assert(result, gc.Equals, 0)
	c.Assert(bufferString(ctx.Stdout), gc.Equals, phrase)
	c.Assert(bufferString(ctx.Stderr), gc.Equals, "")
}

func (s *SuperCommandSuite) TestHelpWithPrefix(c *gc.C) {
	jc := cmd.NewSuperCommand(cmd.SuperCommandParams{Name: "jujutest", UsagePrefix: "juju"})
	jc.Register(&TestCommand{Name: "blah"})
	ctx := testing.Context(c)
	code := cmd.Main(jc, ctx, []string{"blah", "--help"})
	c.Assert(code, gc.Equals, 0)
	stripped := strings.Replace(bufferString(ctx.Stdout), "\n", "", -1)
	c.Assert(stripped, gc.Matches, ".*usage: juju jujutest blah.*blah-doc.*")
}

func (s *BootstrapSuite) TestMissingToolsError(c *gc.C) {
	s.setupAutoUploadTest(c, "1.8.3", "precise")
	context := coretesting.Context(c)
	code := cmd.Main(&BootstrapCommand{}, context, nil)
	c.Assert(code, gc.Equals, 1)
	errText := context.Stderr.(*bytes.Buffer).String()
	expectedErrText := "error: cannot upload bootstrap tools: Juju cannot bootstrap because no tools are available for your environment(.|\n)*"
	c.Assert(errText, gc.Matches, expectedErrText)
}