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: tcc_test.go
    path of file: ./repos/godis/cluster
    
    the code of the file until where you have to start completion: package cluster

import (
	"github.com/hdt3213/godis/redis/connection"
	"github.com/hdt3213/godis/redis/protocol/asserts"
	"math/rand"
	"strconv"
	"testing"
)

func TestRollback(t *testing.T) {
	// rollback uncommitted transaction
	testNodeA := testCluster[0]
	conn := new(connection.FakeConn)
	FlushAll(testNodeA, conn, toArgs("FLUSHALL"))
	txID := rand.Int63()
	txIDStr := strconv.FormatInt(txID, 10)
	keys := []string{"a", "{a}1"}
	groupMap := map[string][]string{
		testNodeA.self: keys,
	}
	args := []string{txIDStr, "DEL"}
	args = append(args
    
func TestRollback(t *testing.T) {
	// rollback uncommitted transaction
	testNodeA := testCluster[0]
	conn := new(connection.FakeConn)
	FlushAll(testNodeA, conn, toArgs("FLUSHALL"))
	txID := rand.Int63()
	txIDStr := strconv.FormatInt(txID, 10)
	keys := []string{"a", "{a}1"}
	groupMap := map[string][]string{
		testNodeA.self: keys,
	}
	args := []string{txIDStr, "DEL"}
	args = append(args, keys...)
	testNodeA.db.Exec(conn, toArgs("SET", "a", "a"))
	ret := execPrepare(testNodeA, conn, makeArgs("Prepare", args...))
	asserts.AssertNotError(t, ret)
	requestRollback(testNodeA, conn, txID, groupMap)
	ret = testNodeA.db.Exec(conn, toArgs("GET", "a"))
	asserts.AssertBulkReply(t, ret, "a")

	// rollback committed transaction
	FlushAll(testNodeA, conn, toArgs("FLUSHALL"))
	testNodeA.db.Exec(conn, toArgs("SET", "a", "a"))
	txID = rand.Int63()
	txIDStr = strconv.FormatInt(txID, 10)
	args = []string{txIDStr, "DEL"}
	args = append(args, keys...)
	ret = execPrepare(testNodeA, conn, makeArgs("Prepare", args...))
	asserts.AssertNotError(t, ret)
	_, err := requestCommit(testNodeA, conn, txID, groupMap)
	if err != nil {
		t.Errorf("del failed %v", err)
		return
	}
	ret = testNodeA.db.Exec(conn, toArgs("GET", "a")) // call db.Exec to skip key router
	asserts.AssertNullBulk(t, ret)
	requestRollback(testNodeA, conn, txID, groupMap)
	ret = testNodeA.db.Exec(conn, toArgs("GET", "a"))
	asserts.AssertBulkReply(t, ret, "a")
}