I want to check if a site allows a user to register using the same email multiple times. I use TestNG framework. How can I do negative testing for the case below?
@Test
public void testRegistration() throws Exception {
driver.get(baseUrl + "/");
driver.findElement(By.cssSelector("span.link.inlblk > strong")).click();
driver.findElement(By.id("register_tab")).click();
driver.findElement(By.id("userEmailRegister")).clear();
driver.findElement(By.id("userEmailRegister")).sendKeys("testmail@testemail.com");
driver.findElement(By.id("userPassRegister")).clear();
driver.findElement(By.id("userPassRegister")).sendKeys("testpassword");
driver.findElement(By.xpath("//*[@id=\"registerForm\"]/div[3]/div/div/label[2]")).click();
driver.findElement(By.xpath("//*[@id=\"registerForm\"]/div[4]/div/div/label[2]")).click();
driver.findElement(By.id("button_register")).click();
driver.findElement(By.cssSelector("span.tdnone > span")).click();
}