Testing GWT app using Selenium 2 - gwt

Question

I'm trying to test a button click using Selenium.
My first page has a button with ID = HOME_START_BUTTON.
When I click this my app then goes to a page with a button with an ID = CONTACTS_ADD_BUTTON.
Here is the code I have to test this.
private static boolean checkPageContainsStartButton()
{
// type search query
// driver.findElement(By.name("q")).sendKeys("qa automation\n");
//Use static finals for these button names
WebElement startButton = driver.findElement(By.id("HOME_START_BTN"));
if (startButton == null)
{
return false;
}
else
{
startButton.click();
}
WebElement myDynamicElement = (new WebDriverWait(driver, 30))
.until(new ExpectedCondition<WebElement>(){
#Override
public WebElement apply(WebDriver d) {
return d.findElement(By.id("CONTACTS_ADD_BTN"));
}});
WebElement addButton = driver.findElement(By.id("CONTACTS_ADD_BTN"));
}
Error stack trace
Command duration or timeout: 28 milliseconds
For documentation on this error, please visit: http://seleniumhq.org/exceptions/no_such_element.html
Build info: version: '2.29.0', revision: '58258c3', time: '2013-01-17 22:47:00'
System info: os.name: 'Windows 7', os.arch: 'x86', os.version: '6.1', java.version: '1.7.0_04'
Session ID: b25e7efb428c98da880826fbf9e68de6
Driver info: org.openqa.selenium.chrome.ChromeDriver
Capabilities [{platform=XP, chrome.chromedriverVersion=26.0.1383.0, acceptSslCerts=false, javascriptEnabled=true, browserName=chrome, rotatable=false, locationContextEnabled=false, version=24.0.1312.57, cssSelectorsEnabled=true, databaseEnabled=false, handlesAlerts=true, browserConnectionEnabled=false, nativeEvents=true, webStorageEnabled=true, applicationCacheEnabled=false, takesScreenshot=true}]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.openqa.selenium.remote.ErrorHandler.createThrowable(ErrorHandler.java:187)
at org.openqa.selenium.remote.ErrorHandler.throwIfResponseFailed(ErrorHandler.java:145)
at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:533)
at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:302)
at org.openqa.selenium.remote.RemoteWebDriver.findElementById(RemoteWebDriver.java:331)
at org.openqa.selenium.By$ById.findElement(By.java:216)
at org.openqa.selenium.remote.RemoteWebDriver.findElement(RemoteWebDriver.java:294)
at WebDriverTestClass.checkPageContainsStartButton(WebDriverTestClass.java:67)
at WebDriverTestClass.main(WebDriverTestClass.java:35)
Test failed.
My test passes if I comment out
WebElement addButton = driver.findElement(By.id("CONTACTS_ADD_BTN"));
So basically Selenium does not appear to be able to see the new widgets on the browser window when I do a button click

Answer 1

You need to add a wait till the first button action is done. Use a default constant across all waits in your app. DEFAULT_RPC_WAIT, DEFAULT_SCREEN_WAIT etc. It would help to know where you have set up your waits by using Constants instead of just magic numbers.
Also reference GWT guidelines w.r.t to Selenium - https://developers.google.com/web-toolkit/doc/latest/DevGuideTestingRemoteTesting

Answer 2

you post that ID = HOME_START_BUTTON
but in your code I see: By.id("HOME_START_BTN")
from WebDriver interface comments for findElement method:
findElement should not be used to look for non-present elements, use findElements(By) and assert zero length response instead.
/**
* Find the first {#link WebElement} using the given method.
* This method is affected by the 'implicit wait' times in force at the time of execution.
* The findElement(..) invocation will return a matching row, or try again repeatedly until
* the configured timeout is reached.
*
* findElement should not be used to look for non-present elements, use {#link #findElements(By)}
* and assert zero length response instead.
*
* #param by The locating mechanism
* #return The first matching element on the current page
* #throws NoSuchElementException If no matching elements are found
* #see org.openqa.selenium.By
* #see org.openqa.selenium.WebDriver.Timeouts
*/
WebElement findElement(By by);