testng中方法为什么执行两次?

newtest.java

package COM.CITSAMER;
import org.testng.annotations.Test;
public class NewTest extends CommonClass {

@Test
public void bingSearchWithOpenNew() {
 getSignIn(username,password); 
    }   
}

CommonClass.java

package COM.CITSAMER;

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

public class CommonClass {
 
 WebDriver driver = new FirefoxDriver(); 
 String baseUrl ="http://wwww.126.com";
 String username="dian***";
 String password="2198****";
 
@DataProvider(name = "test") 
public Object[][]createData() {
 
return new Object[][] { 
    { username, password},  
  }; 
 } 

@Test(dataProvider = "test")
public void getSignIn(String aUsername,String aPassword){
 driver.get(baseUrl);
 driver.findElement(By.id("idInput")).clear();
 driver.findElement(By.id("idInput")).sendKeys(aUsername);
 driver.findElement(By.id("pwdInput")).clear();
 driver.findElement(By.id("pwdInput")).sendKeys(aPassword);
 driver.findElement(By.id("loginBtn")).click();
 try {
  Thread.sleep(2000);
 } catch (InterruptedException e) {
  e.printStackTrace();
 }
if(!driver.getCurrentUrl().startsWith("http://webmail.mail.126.com/js4/main.jsp")){
 System.out.println("sign in not success, pls check..."); 
}
}
}