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: bulkinserter_test.go
    path of file: ./repos/go-zero/core/stores/sqlx
    
    the code of the file until where you have to start completion: package sqlx

import (
	"context"
	"database/sql"
	"errors"
	"strconv"
	"strings"
	"sync"
	"sync/atomic"
	"testing"

	"github.com/DATA-DOG/go-sqlmock"
	"github.com/stretchr/testify/assert"
	"github.com/zeromicro/go-zero/core/stores/dbtest"
)

type mockedConn struct {
	query          string
	args           []any
	execErr        error
	updateCallback func(query string, args []any)
}

func (c *mockedConn) ExecCtx(_ context.Context, query string, args ...any) (sql.Result, error) {
	c.query = query
	c.args = args
	if c.updateCallback != nil {
		c.updateCallback(query, args)
	}

	return nil, c.execErr
}

func 
    
func TestBulkInserter(t *testing.T) {
	dbtest.RunTest(t, func(db *sql.DB, mock sqlmock.Sqlmock) {
		var conn mockedConn
		inserter, err := NewBulkInserter(&conn, `INSERT INTO classroom_dau(classroom, user, count) VALUES(?, ?, ?)`)
		assert.Nil(t, err)
		for i := 0; i < 5; i++ {
			assert.Nil(t, inserter.Insert("class_"+strconv.Itoa(i), "user_"+strconv.Itoa(i), i))
		}
		inserter.Flush()
		assert.Equal(t, `INSERT INTO classroom_dau(classroom, user, count) VALUES `+
			`('class_0', 'user_0', 0), ('class_1', 'user_1', 1), ('class_2', 'user_2', 2), `+
			`('class_3', 'user_3', 3), ('class_4', 'user_4', 4)`,
			conn.query)
		assert.Nil(t, conn.args)
	})
}