func TestDatacentersFunc_missingData(t *testing.T) {
	d, err := dep.ParseDatacenters()
	if err != nil {
		t.Fatal(err)
	}

	brain := NewBrain()

	used := make(map[string]dep.Dependency)
	missing := make(map[string]dep.Dependency)

	f := datacentersFunc(brain, used, missing)
	result, err := f()
	if err != nil {
		t.Fatal(err)
	}

	expected := []string{}
	if !reflect.DeepEqual(result, expected) {
		t.Errorf("expected %q to be %q", result, expected)
	}

	if _, ok := used[d.HashCode()]; !ok {
		t.Errorf("expected dep to be used")
	}

	if _, ok := missing[d.HashCode()]; !ok {
		t.Errorf("expected dep to be missing")
	}
}

func TestDatacentersFunc_hasData(t *testing.T) {
	d, err := dep.ParseDatacenters()
	if err != nil {
		t.Fatal(err)
	}

	dcs := []string{"dc1", "dc2"}

	brain := NewBrain()
	brain.Remember(d, dcs)

	used := make(map[string]dep.Dependency)
	missing := make(map[string]dep.Dependency)

	f := datacentersFunc(brain, used, missing)
	result, err := f()
	if err != nil {
		t.Fatal(err)
	}

	expected := dcs
	if !reflect.DeepEqual(result, expected) {
		t.Errorf("expected %q to be %q", result, expected)
	}

	if len(missing) != 0 {
		t.Errorf("expected missing to have 0 elements, but had %d", len(missing))
	}

	if _, ok := used[d.HashCode()]; !ok {
		t.Errorf("expected dep to be used")
	}
}

// datacentersFunc returns or accumulates datacenter dependencies.
func datacentersFunc(brain *Brain,
	used, missing map[string]dep.Dependency) func(...string) ([]string, error) {
	return func(s ...string) ([]string, error) {
		result := make([]string, 0)

		d, err := dep.ParseDatacenters(s...)
		if err != nil {
			return result, err
		}

		addDependency(used, d)

		if value, ok := brain.Recall(d); ok {
			return value.([]string), nil
		}

		addDependency(missing, d)

		return result, nil
	}
}

func TestExecute_renders(t *testing.T) {
	// Stub out the time.
	now = func() time.Time { return time.Unix(0, 0).UTC() }

	in := test.CreateTempfile([]byte(`
		API Functions
		-------------
		datacenters:{{ range datacenters }}
			{{.}}{{ end }}
		file: {{ file "/path/to/file" }}
		key: {{ key "config/redis/maxconns" }}
		ls:{{ range ls "config/redis" }}
			{{.Key}}={{.Value}}{{ end }}
		node:{{ with node }}
			{{.Node.Node}}{{ range .Services}}
				{{.Service}}{{ end }}{{ end }}
		nodes:{{ range nodes }}
			{{.Node}}{{ end }}
		service:{{ range service "webapp" }}
			{{.Address}}{{ end }}
		service (any):{{ range service "webapp" "any" }}
			{{.Address}}{{ end }}
		service (tag.Contains):{{ range service "webapp" }}{{ if .Tags.Contains "production" }}
			{{.Node}}{{ end }}{{ end }}
		services:{{ range services }}
			{{.Name}}{{ end }}
		tree:{{ range tree "config/redis" }}
			{{.Key}}={{.Value}}{{ end }}
		vault: {{ with vault "secret/foo/bar" }}{{.Data.zip}}{{ end }}

		Helper Functions
		----------------
		byKey:{{ range $key, $pairs := tree "config/redis" | byKey }}
			{{$key}}:{{ range $pairs }}
				{{.Key}}={{.Value}}{{ end }}{{ end }}
		byTag (health service):{{ range $tag, $services := service "webapp" | byTag }}
			{{$tag}}:{{ range $services }}
				{{.Address}}{{ end }}{{ end }}
		byTag (catalog services):{{ range $tag, $services := services | byTag }}
			{{$tag}}:{{ range $services }}
				{{.Name}}{{ end }}{{ end }}
		contains:{{ range service "webapp" }}{{ if .Tags | contains "production" }}
			{{.Node}}{{ end }}{{ end }}
		env: {{ env "foo" }}
		explode:{{ range $k, $v := tree "config/redis" | explode }}
			{{$k}}{{$v}}{{ end }}
		in:{{ range service "webapp" }}{{ if in .Tags "production" }}
			{{.Node}}{{ end }}{{ end }}
		loop:{{ range loop 3 }}
			test{{ end }}
		loop(i):{{ range $i := loop 5 8 }}
			test{{$i}}{{ end }}
		join: {{ "a,b,c" | split "," | join ";" }}
		parseBool: {{"true" | parseBool}}
		parseFloat: {{"1.2" | parseFloat}}
		parseInt: {{"-1" | parseInt}}
		parseJSON (string):{{ range $key, $value := "{\"foo\": \"bar\"}" | parseJSON }}
			{{$key}}={{$value}}{{ end }}
		parseJSON (file):{{ range $key, $value := file "/path/to/json/file" | parseJSON }}
			{{$key}}={{$value}}{{ end }}
		parseJSON (env):{{ range $key, $value := env "json" | parseJSON }}
			{{$key}}={{$value}}{{ end }}
		parseUint: {{"1" | parseUint}}
		plugin: {{ file "/path/to/json/file" | plugin "echo" }}
		timestamp: {{ timestamp }}
		timestamp (formatted): {{ timestamp "2006-01-02" }}
		regexMatch: {{ file "/path/to/file"  | regexMatch ".*[cont][a-z]+" }}
		regexMatch: {{ file "/path/to/file"  | regexMatch "v[0-9]*" }}
		regexReplaceAll: {{ file "/path/to/file" | regexReplaceAll "\\w" "x" }}
		replaceAll: {{ file "/path/to/file" | replaceAll "some" "this" }}
		split:{{ range "a,b,c" | split "," }}
			{{.}}{{end}}
		toLower: {{ file "/path/to/file" | toLower }}
		toJSON: {{ tree "config/redis" | explode | toJSON }}
		toJSONPretty:
{{ tree "config/redis" | explode | toJSONPretty }}
		toTitle: {{ file "/path/to/file" | toTitle }}
		toUpper: {{ file "/path/to/file" | toUpper }}
		toYAML:
{{ tree "config/redis" | explode | toYAML }}

		Math Functions
		--------------
		add:{{ 2 | add 2 }}
		subtract:{{ 2 | subtract 2 }}
		multiply:{{ 2 | multiply 2 }}
		divide:{{ 2 | divide 2 }}
`), t)
	defer test.DeleteTempfile(in, t)

	tmpl, err := NewTemplate(in.Name())
	if err != nil {
		t.Fatal(err)
	}

	brain := NewBrain()

	var d dep.Dependency

	d, err = dep.ParseDatacenters()
//.........这里部分代码省略.........