Login page with Selenium webdriver I am automating a login page. I am using the page object design pattern Selenium with Java. What should I improve on in my code?

package Pages;

import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;


public class LoginPage 
{
    private WebDriver driver;

       @FindBy(id="userName")
       WebElement username;
       @FindBy(id="password")
       WebElement password;
       @FindBy(className="btn-info")
       WebElement button;
       public LoginPage(WebDriver driver)
       {
        //initialize elements
          PageFactory.initElements(driver, this);

       }
       public void set_username(String usern)
       {
        username.clear();
        username.sendKeys(usern);
       }
       public void set_password(String userp)
       {
        password.clear();
        password.sendKeys(userp);
       }
       public void click_button()
       {
        button.submit();
       }
}




package Test;
import org.testng.annotations.Test;


import Pages.LoginPage;
import org.testng.Assert;
import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.testng.annotations.AfterTest;
import org.testng.annotations.BeforeTest;



public class LoginTest
{
WebDriver driver;
@BeforeTest
public void setup()
{
    System.setProperty("webdriver.firefox.marionette","pathToGeckodriver");
    driver=new FirefoxDriver();
    driver.manage().window().maximize();
    driver.get("https://twhyderabad.github.io/demo_site/");
}
@Test(priority=5)
public void verify1()
{
    LoginPage login=new LoginPage(driver);
    login.set_username("admin");
    login.set_password("admin");
    login.click_button();
    Assert.assertTrue(driver.getPageSource().contains("Blog"));
}
@Test(priority=1)
public void verify2()
{
    LoginPage login=new LoginPage(driver);
    login.set_username("adm");
    login.set_password("admin");
    login.click_button();
    Assert.assertEquals(driver.findElement(By.xpath("//*[@id='errorMessage']")).getText(),"Wrong username or password!");
}
@Test(priority=2)
public void verify3()
{
    LoginPage login=new LoginPage(driver);
    login.set_username("admin");
    login.set_password("adm");
    login.click_button();
    Assert.assertEquals(driver.findElement(By.xpath("//*[@id='errorMessage']")).getText(),"Wrong username or password!");
}
@Test(priority=3)
public void verify4()
{
    LoginPage login=new LoginPage(driver);
    login.set_username("adm");
    login.set_password("adm");
    login.click_button();
    Assert.assertEquals(driver.findElement(By.xpath("//*[@id='errorMessage']")).getText(),"Wrong username or password!");
}
@Test(priority=4)
public void verify5()
{
    LoginPage login=new LoginPage(driver);
    login.set_username("");
    login.set_password("");
    login.click_button();
    Assert.assertEquals(driver.findElement(By.xpath("//*[@id='errorMessage']")).getText(),"Wrong username or password!");
}
@AfterTest
public void close()
{
    driver.close();
}
}
The method names are consistent, but usually camelcase is advocated.
Indentation is inconsistent, but maybe that's from pasting it here?
Variables like usern and userp are bad, why not name and
password or something that's readable?
Why is the window maximised?  The site doesn't look that's necessary
for anything.
Consider having a login method instead of repeating the same code
five times, e.g. login.login("admin", "admin").
Extract common code to a new method.  That is, for four of the five
tests it could just be checkFailedLogin("foo", "bar").
IDs are/should be unique to elements in HTML, so the XPath is way too
complicated, consider just By.id (and By.className and By.name
for that matter).
Also consider returning the expected page from that method so that
it's clear from the code, MainPage main = login.login(...); and have
it raise an exception if the new page doesn't match what was expected
(e.g. we usually have an invisible value unique to each page to
identify it in tests, but there are probably other ways to do that).