Author: Jimmy

Google Search Results Weirdness

Over on Twitter, @semperos has brought an interesting point to my attention. My posts from this blog, when indexed by Google, have the date ‘August 29th 1997’ in the meta data relating to the result. This gives the impression that posts were written on this date:

Google Search Results

It seems that GoogleBot is taking the date from the text in the banner on my site:

My website banner

(From one of my favourite movies)

This is contrary to everything I’ve read, which states that Google’s crawler is either smart enough to recognise the date of your last post, or this is the date of the last crawl. The above screen captures obviously rule out both of these possibilities.

It looks, to the Google outsider like myself, that GoogleBot is just taking the first date it finds on a page it is crawling, and using that in the description on the search results page.

If anyone from Google happens to read this – I’d love an explanation or clarification…

Taking screenshots with Selenium WebDriver

Time to do something a bit more useful using Selenium WebDriver. Taking screenshots as we cycle through our web pages has obvious advantages for unit testing. Firstly we can just run an application overnight, have it visit every page on our website, and review the screenshots for obvious bugs the next morning before releasing to QA. Secondly, we can screenshot our localized websites, and have them linguistically reviewed, or hand off the English screenshots to our translators to provide context during the translation process.

Taking screenshots with WebDriver is exceptionally easy. The thing I like about it most, is that it takes a screenshot of just the area of the browser in which the content resides – no IE/FF/Chrome toolbars etc. But, it also takes the entire webpage – even content not visible on the screen at that time. This is a great feature. I’ve had the problem in the past with long web pages, ones for example that contain a EULA or other long document, where the screenshots had to be taken at intervals as the page scrolled. Obviously not the best process, and not very reusable code.

As mentioned in a previous post, I’m using the Selenium Client Driver for C#. I’ve created a library into which I’m adding useful functions like taking screenshots etc.

The code to take a screenshot is not complex:

using OpenQA.Selenium.IE;
using OpenQA.Selenium;
using System.Drawing.Imaging;

public void TakeScreenshot(IWebDriver driver, string saveLocation)
{
    ITakesScreenshot screenshotDriver = driver as ITakesScreenshot;
    Screenshot screenshot = screenshotDriver.GetScreenshot();
    screenshot.SaveAsFile(saveLocation, ImageFormat.Png);
}

The libraries referenced can be found in the Selenium Client Driver for C# package which can be downloaded from the Selenium website. These will need to be added to your C# project.

Notice in the above function we pass an ‘IWebDriver’ Object, as opposed to a specific InternetExplorerDriver, FirefoxDriver etc. This means this function can be used regardless of which browser you are dealing with.

Using the function is also a trival matter. Let’s browse to Google and take a screenshot, saving it in the root of the ‘C:\’ drive:

IWebDriver driver = new InternetExplorerDriver();
driver.Navigate().GoToUrl("http://www.google.com");
TakeScreenshot(driver, @"C:\screenshot.png");

Note that the TakeScreenshot function can be customized to use any image format – in fact it should probably be a function parameter. I chose PNG simply because of the small size of the generated image.

Running Selenium Tests with C# & NUnit

Something I’m working on currently requires some automation of a web browser, so what a perfect opportunity to get some exposure to Selenium.

In this post I’ll outline the basics of creating and running a simple Selenium test using Selenium and NUnit. The implementation language will be C#. To get started, you will need to download the following:

Extract the Selenium Client Driver files, these DLL’s will be referenced in the Visual Studio project we create. Install NUnit using the .msi installer.

Now, let’s create the actual test:

  1. Launch Visual Studio 2010 and create a new class library project.
  2. Add a reference to nunit.framework.dll. This can be found under the NUnit installation directory at ‘bin\net-2.0\framework’.
  3. Add references to all the DLL’s contained in the Selenium Client Driver package you downloaded earlier.
  4. We’re now ready to add the code that will run a Selenium test. Add the following code to your class library project:
using NUnit.Framework;
using OpenQA.Selenium;
using OpenQA.Selenium.IE;

namespace FirstSeleniumTest
{
    [TestFixture]
    public class SeleniumTest
    {
        private IWebDriver driver;

        [SetUp]
        public void SetUp()
        {
            driver = new InternetExplorerDriver();
        }

        [Test]
        public void TestGoogle()
        {
            driver.Navigate().GoToUrl("http://www.google.com");
        }

        [TearDown]
        public void TearDown()
        {
            driver.Quit();
            driver.Dispose();
        } 
    }
}

The above code should be pretty easy to understand. Notice the annotations around the functions.

  • [SetUp] – This is where any test setup should be completed. In the above example we’re creating a new instance of InternetExplorerDriver, setting it up for our test to run later.
  • [Test] – This is where the test steps are defined. In this example, we’re just navigating to Google.
  • [TearDown] – In this section, any steps to be taken to cleanup the environment after your test has run can be defined. Here, all we’ll do is close Internet Explorer

Now that we have written a simple test, let’s try running it using NUnit. Before moving on, ensure that the above code builds successfully in your environment.

To run the test it’s just a matter of launching NUnit and opening up the DLL built from the Visual Studio project created above. You should see the ‘TestGoogle’ test listed. Simply select the test and hit the ‘Run’ button to initiate the test. You will see Internet Explorer launch, and then close.

NUnit

One thing you may need to do, depending on your IE version, is to disable protected mode for Internet and Restricted Zones in Internet Explorer Security Settings (don’t forget to re-enable these once you’ve finished experimenting with Selenium).

In a future post, I’ll outline how to do more complex tasks during your tests such as taking screenshots and navigating around web pages under tests.

Refactoring horrible nested if-else statements

I wrote this at some point this week, I was looking back at it tonight and released how truly awful it looks:

if(filePath.Contains(".CSS"))
    return true;
else
    return false;
else if(filePath.Contains(".JS"))
    return true;
else
    return false;
else if(filePath.Contains("_STR"))
    return true;
else
    return false;
else if(filePath.Contains(".VBS"))
    return true;
else
    return false;
else if(filePath.Contains(".HTM"))
    return true;
else
    return false;
else if(filePath.Contains(".BMP"))
    return true;
else
    return false;
else if(filePath.Contains("GIF"))
    return true;
else
    return false;

Terrible huh? What was I thinking?

How much better does this look:


bool copyFile;

copyFile = (filePath.Contains(".CSS"))      ? true:
               (filePath.Contains(".JS"))   ? true:
               (filePath.Contains("_STR"))  ? true:
               (filePath.Contains(".VBS"))  ? true:
               (filePath.Contains(".HTM"))  ? true:
               (filePath.Contains(".BMP"))  ? true:
               (filePath.Contains("GIF"))   ? true:
                                              false;
return copyFile;

I like it, impressed with that one for a Friday.

Handling Exceptions on Windows Phone 7

In this post I’ll outline how to deal with exceptions in a Windows Phone 7 application. Ideally when an exception happens, we want to display some meaningful information to the user that can be provided to the developer to aid in the debugging of the issue. The worst thing that can happen is for the application to crash and just exit. This can lead to frustration on the users part (as I’ve experienced with the official Twitter application on iOS 4.0), or worse dissuade a user from purchasing any other applications bearing your name.

In this example, when an exception occurs, we’ll ensure that we navigate to an error page, and display the stack trace. Aside, this is obviously not the best thing to display to an end user. The best approach may be to display a generic error message with an option to report the error, which then emails the exception information to your support address. I leave that as an exercise to the reader, in this example, we’ll just display the stack trace information directly to the user:

1. Add a new Windows Phone Portrait Page to your Windows Phone 7 project in Visual Studio. For the purpose of this example, I’ve named the page ‘Error.xaml’.

2. In ‘Error.xaml’, locate the ‘LayoutRoot’ Grid element, and replace its content with the following:















3. The page you created above will act as the container for any exceptions that we need to display. Next, open up ‘Error.xaml.cs’, and add the following code:


using System.Windows.Navigation;
...
...

public static Exception Exception;

// Executes when the user navigates to this page.
protected override void OnNavigatedTo(NavigationEventArgs e)
{
ErrorText.Text = Exception.ToString();
}

This sets up an Exception Object that is hooked up to ErrorText.Text upon navigating to the page.

4. Finally, we need to hook up an event handler that ensures that we navigate to this page whenever an unhandled exception occurs. This is done from ‘App.xaml.cs’. Open up ‘App.xaml.cs’, and replace the content of the ‘Application_UnhandledException’ function with the following code:


if (System.Diagnostics.Debugger.IsAttached)
{
// An unhandled exception has occurred; break in the debugger
System.Diagnostics.Debugger.Break();
}

// Running on a device / emulator without debugging
e.Handled = true;
Error.Exception = e.ExceptionObject;
(RootVisual as Microsoft.Phone.Controls.PhoneApplicationFrame).Source =
new Uri("/Error.xaml", UriKind.Relative);

If you have completed the above steps correctly, then whenever an unhandled exception occurs in your application, the application will navigate to this page, and display the exception stack trace.

To verify these steps, add a button to your ‘MainPage.xaml’ and have it link to a page that doesn’t exist, e.g.


NavigationService.Navigate(new Uri("/NotHere.xaml", UriKind.Relative));

Launch the application in the emulator, and click the button you just created, (You’ll need to launch without debugging). The result should be navigation to ‘Error.xaml’ with the exception details:

Windows Phone Error Example

WPF – Binding Data in an XML file to a ComboBox

Some things in WPF are very different from Windows Forms programming. Lately, I’ve been working on my first real UI in which I’ve used WPF over Windows Forms. Using XAML takes a little bit of getting used to, but I’m finding that I have a lot more control over the UI, along with the obvious advantage of seperating the UI presentation from the actual application logic.

Just the other day I needed to create a ComboBox control on a section of my UI, the items in which would need to be loaded from an XML file at runtime. The XML file was to be included as a resource.

The XML file looked something like this:






...

I wanted the ‘name’ attribute from each Language node to be bound to my ComboBox. In order to do this, first we need to define the XML file as a resource in our XAML:





...
...

Then, we just need to add the ItemsSource, SelectedValuePath, and DisplayMemberPath to the ComboBox XAML, specifying the resource we declared earlier, and the attribute that we want to bind:




Note the ‘SelectedItem’ can be set as well from the XAML, It’s set to ‘Arabic’ in the above example.