You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: manager_test.go
    path of file: ./repos/docker-ce/components/cli/cli-plugins/manager
    
    the code of the file until where you have to start completion: package manager

import (
	"strings"
	"testing"

	"github.com/docker/cli/cli/config"
	"github.com/docker/cli/cli/config/configfile"
	"github.com/docker/cli/internal/test"
	"github.com/spf13/cobra"
	"gotest.tools/v3/assert"
	"gotest.tools/v3/fs"
)

func TestListPluginCandidates(t *testing.T) {
	// Populate a selection of directories with various shadowed and bogus/obscure plugin candidates.
	// For the purposes of this test no contents is required and permissions are irrelevant.
	dir := fs.NewDir(t, t.
    
func TestGetPluginDirs(t *testing.T) {
	cli := test.NewFakeCli(nil)

	pluginDir, err := config.Path("cli-plugins")
	assert.NilError(t, err)
	expected := append([]string{pluginDir}, defaultSystemPluginDirs...)

	var pluginDirs []string
	pluginDirs, err = getPluginDirs(cli)
	assert.Equal(t, strings.Join(expected, ":"), strings.Join(pluginDirs, ":"))
	assert.NilError(t, err)

	extras := []string{
		"foo", "bar", "baz",
	}
	expected = append(extras, expected...)
	cli.SetConfigFile(&configfile.ConfigFile{
		CLIPluginsExtraDirs: extras,
	})
	pluginDirs, err = getPluginDirs(cli)
	assert.DeepEqual(t, expected, pluginDirs)
	assert.NilError(t, err)
}