element =
driver.findElement(By.xpath("//form[@name='someForm']/input[@id='username']"));
String originalValue = element.getAttribute("value");
assertEquals(originalValue, ("change"));
element.clear();
element.sendKeys("some text");
element = driver.findElement(By.xpath("//form[@name='someForm']/input[@id='username']"));
String newFormValue = element.getAttribute("value");
assertEquals(newFormValue, ("some text"));