package user

import (
	"bufio"
	"bytes"
	"errors"
	"fmt"
	"io"
	"os"
	"strconv"
)

func listGroupsFromReader(u *User, r io.Reader) ([]string, error) {
	if u.Username == "" {
		return nil, errors.New("user: list groups: empty username")
	}
	primaryGid, err := strconv.Atoi(u.Gid)
	if err != nil {

	{in: "", user: "joanna", gid: "bad", err: true},
}

func TestListGroups(t *testing.T) {
	for _, tc := range listGroupsTests {
		u := &User{Username: tc.user, Gid: tc.gid}
		got, err := listGroupsFromReader(u, strings.NewReader(tc.in))
		if tc.err {
			if err == nil {
				t.Errorf("listGroups(%q): got nil; want error", tc.user)
			}
			continue // no more checks
		}
		if err != nil {