Saturday, January 11, 2014

Take a screenshot using Selenium WebDriver with Java

WebDriver driver = new FirefoxDriver();
driver.get("http://www.google.com/");
File scrFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
// Now you can do whatever you need to do with it, for example copy somewhere
FileUtils.copyFile(scrFile, new File("c:\\tmp\\screenshot.png"));

Drag And Drop


Here’s an example of using the Actions class to perform a drag and drop. Native events are required to be enabled.
WebElement element = driver.findElement(By.name("source"));
WebElement target = driver.findElement(By.name("target"));

(new Actions(driver)).dragAndDrop(element, target).perform();

Changing the User Agent


This is easy with the Firefox Driver:
FirefoxProfile profile = new FirefoxProfile();
profile.addAdditionalPreference("general.useragent.override", "some UA string");
WebDriver driver = new FirefoxDriver(profile);

Cookies

Before we leave these next steps, you may be interested in understanding how to use cookies. First of all, you need to be on the domain that the cookie will be valid for. If you are trying to preset cookies before you start interacting with a site and your homepage is large / takes a while to load an alternative is to find a smaller page on the site, typically the 404 page is small (http://example.com/some404page)

// Go to the correct domain
driver.get("http://www.example.com");

// Now set the cookie. This one's valid for the entire domain
Cookie cookie = new Cookie("key", "value");
driver.manage().addCookie(cookie);

// And now output all the available cookies for the current URL
Set<Cookie> allCookies = driver.manage().getCookies();
for (Cookie loadedCookie : allCookies) {
    System.out.println(String.format("%s -> %s", loadedCookie.getName(),  
loadedCookie.getValue()));
}

// You can delete cookies in 3 ways
// By name
driver.manage().deleteCookieNamed("CookieName");
// By Cookie
driver.manage().deleteCookie(loadedCookie);
// Or all of them
driver.manage().deleteAllCookies();

Navigation: History and Location

Popup Dialogs

Moving Between Windows and Frames


Some web applications have many frames or multiple windows. WebDriver supports moving between named windows using the “switchTo” method:
driver.switchTo().window("windowName");
All calls to driver will now be interpreted as being directed to the particular window. But how do you know the window’s name? Take a look at the javascript or link that opened it:
<a href="somewhere.html" target="windowName">Click here to open a new window</a>
Alternatively, you can pass a “window handle” to the “switchTo().window()” method. Knowing this, it’s possible to iterate over every open window like so:
for (String handle : driver.getWindowHandles()) {
    driver.switchTo().window(handle);
}
You can also switch from frame to frame (or into iframes):
driver.switchTo().frame("frameName");
It’s possible to access subframes by separating the path with a dot, and you can specify the frame by its index too. That is:
driver.switchTo().frame("frameName.0.child");
would go to the frame named “child” of the first subframe of the frame called “frameName”. All frames are evaluated as if from *top*.

User Input - Filling In Forms


We’ve already seen how to enter text into a textarea or text field, but what about the other elements? You can “toggle” the state of checkboxes, and you can use “click” to set something like an OPTION tag selected. Dealing with SELECT tags isn’t too bad:
WebElement select = driver.findElement(By.tagName("select"));
List<WebElement> allOptions = select.findElements(By.tagName("option"));
for (WebElement option : allOptions) {
    System.out.println(String.format("Value is: %s", option.getAttribute("value")));
    option.click();
}
This will find the first “SELECT” element on the page, and cycle through each of its OPTIONs in turn, printing out their values, and selecting each in turn. As you will notice, this isn’t the most efficient way of dealing with SELECT elements. WebDriver’s support classes include one called “Select”, which provides useful methods for interacting with these.
Select select = new Select(driver.findElement(By.tagName("select")));
select.deselectAll();
select.selectByVisibleText("Edam");
This will deselect all OPTIONs from the first SELECT on the page, and then select the OPTION with the displayed text of “Edam”.
Once you’ve finished filling out the form, you probably want to submit it. One way to do this would be to find the “submit” button and click it:
driver.findElement(By.id("submit")).click();
Alternatively, WebDriver has the convenience method “submit” on every element. If you call this on an element within a form, WebDriver will walk up the DOM until it finds the enclosing form and then calls submit on that. If the element isn’t in a form, then the NoSuchElementException will be thrown:
element.submit();

Locating UI Elements (WebElements)

Locating elements in WebDriver can be done on the WebDriver instance itself or on a WebElement. Each of the language bindings expose a “Find Element” and “Find Elements” method. The first returns a WebElement object otherwise it throws an exception. The latter returns a list of WebElements, it can return an empty list if no DOM elements match the query.
The “Find” methods take a locator or query object called “By”. “By” strategies are listed below.

By ID

This is the most efficient and preferred way to locate an element. Common pitfalls that UI developers make is having non-unique id’s on a page or auto-generating the id, both should be avoided. A class on an html element is more appropriate than an auto-generated id.
Example of how to find an element that looks like this:
<div id="coolestWidgetEvah">...</div>

WebElement element = driver.findElement(By.id("coolestWidgetEvah"));

By Class Name

“Class” in this case refers to the attribute on the DOM element. Often in practical use there are many DOM elements with the same class name, thus finding multiple elements becomes the more practical option over finding the first element.
Example of how to find an element that looks like this:
<div class="cheese"><span>Cheddar</span></div><div class="cheese"><span>Gouda</span></div>

List<WebElement> cheeses = driver.findElements(By.className("cheese"));

By Tag Name

The DOM Tag Name of the element.
Example of how to find an element that looks like this:
<iframe src="..."></iframe>

WebElement frame = driver.findElement(By.tagName("iframe"));

By Name

Find the input element with matching name attribute.
Example of how to find an element that looks like this:
<input name="cheese" type="text"/>

WebElement cheese = driver.findElement(By.name("cheese"));

By CSS

Like the name implies it is a locator strategy by css. Native browser support is used by default, so please refer to w3c css selectors <http://www.w3.org/TR/CSS/#selectors> for a list of generally available css selectors. If a browser does not have native support for css queries, then Sizzle is used. IE 6,7 and FF3.0 currently use Sizzle as the css query engine.
Beware that not all browsers were created equal, some css that might work in one version may not work in another.
Example of to find the cheese below:
<div id="food"><span class="dairy">milk</span><span class="dairy aged">cheese</span></div>

WebElement cheese = driver.findElement(By.cssSelector("#food span.dairy.aged"));

By XPATH

At a high level, WebDriver uses a browser’s native XPath capabilities wherever possible. On those browsers that don’t have native XPath support, we have provided our own implementation. This can lead to some unexpected behaviour unless you are aware of the differences in the various xpath engines.
Driver Tag and Attribute Name Attribute Values Native XPath Support
HtmlUnit Driver Lower-cased As they appear in the HTML Yes
Internet Explorer Driver Lower-cased As they appear in the HTML No
Firefox Driver Case insensitive As they appear in the HTML Yes
This is a little abstract, so for the following piece of HTML:
<input type="text" name="example" />
<INPUT type="text" name="other" />

List<WebElement> inputs = driver.findElements(By.xpath("//input"));
The following number of matches will be found
XPath expression HtmlUnit Driver Firefox Driver Internet Explorer Driver
//input 1 (“example”) 2 2
//INPUT 0 2 0
Sometimes HTML elements do not need attributes to be explicitly declared because they will default to known values. For example, the “input” tag does not require the “type” attribute because it defaults to “text”. The rule of thumb when using xpath in WebDriver is that you should not expect to be able to match against these implicit attributes.

Using JavaScript

You can execute arbitrary javascript to find an element and as long as you return a DOM Element, it will be automatically converted to a WebElement object.
Simple example on a page that has jQuery loaded:

WebElement element = (WebElement) ((JavascriptExecutor)driver).executeScript("return $('.cheese')[0]");
Finding all the input elements to the every label on a page:

List<WebElement> labels = driver.findElements(By.tagName("label"));
List<WebElement> inputs = (List<WebElement>) ((JavascriptExecutor)driver).executeScript(
    "var labels = arguments[0], inputs = []; for (var i=0; i < labels.length; i++){" +
    "inputs.push(document.getElementById(labels[i].getAttribute('for'))); } return inputs;", labels);