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: namespace_test.go
    path of file: ./repos/shellhub/api/store/mongo
    
    the code of the file until where you have to start completion: package mongo

import (
	"context"
	"sort"
	"testing"
	"time"

	"github.com/shellhub-io/shellhub/api/pkg/dbtest"
	"github.com/shellhub-io/shellhub/api/pkg/fixtures"
	"github.com/shellhub-io/shellhub/api/pkg/guard"
	"github.com/shellhub-io/shellhub/api/store"
	"github.com/shellhub-io/shellhub/pkg/api/query"
	"github.com/shellhub-io/shellhub/pkg/cache"
	"github.com/shellhub-io/shellhub/pkg/models"
	"github.com/stretchr/testify/assert"
)

func TestNamespaceList(t *testing.T) {
	type Expected struct {
		ns    []models.Namespace
		count int
		err   error
	}

	cases := []struct {
		description string
		page        query.Paginator
		filters     query.Filters
		export      bool
		fixtures    []string
		expected    Expected
	}{
		{
			description: "succeeds 
    
func TestNamespaceEditMember(t *testing.T) {
	cases := []struct {
		description string
		tenant      string
		member      string
		role        string
		fixtures    []string
		expected    error
	}{
		{
			description: "fails when user is not found",
			tenant:      "nonexistent",
			member:      "000000000000000000000000",
			role:        guard.RoleObserver,
			fixtures:    []string{fixtures.FixtureNamespaces},
			expected:    ErrUserNotFound,
		},
		{
			description: "succeeds when tenant and user is found",
			tenant:      "00000000-0000-4000-0000-000000000000",
			member:      "6509e169ae6144b2f56bf288",
			role:        guard.RoleOperator,
			fixtures:    []string{fixtures.FixtureNamespaces},
			expected:    nil,
		},
	}

	db := dbtest.DBServer{}
	defer db.Stop()

	mongostore := NewStore(db.Client().Database("test"), cache.NewNullCache())
	fixtures.Init(db.Host, "test")

	for _, tc := range cases {
		t.Run(tc.description, func(t *testing.T) {
			assert.NoError(t, fixtures.Apply(tc.fixtures...))
			defer fixtures.Teardown() // nolint: errcheck

			err := mongostore.NamespaceEditMember(context.TODO(), tc.tenant, tc.member, tc.role)
			assert.Equal(t, tc.expected, err)
		})
	}
}