code-diesel

In the previous Selenium posts we saw how to use the selenium IDE for testing web pages. In this post we will see how to extend the Selenium IDE by adding our own custom commands.

Selenium IDE offers many useful commands (often called Selenese) for testing purposes. You use this sequence of commands to create various tests. But many times these commands are not sufficient and you need to add your own custom commands. For example a reader recently requested on how to input unique email ids for testing. Of course you can easily do this using the Selenium RC server and a language like PHP or Java. But we want to accomplish this in the IDE itself.

Types of Selenium commands

Selenium commands come in three varieties : Actions, Accessors and Assertions. Each Selenium command being given in the format below:

Actions are commands which in general modify the state of the application; click, typeKeys, deleteCookie etc. are all actions. Many actions also come with a sibling with a “AndWait” suffix added; e.g. ‘typeKeysAndWait’. This tells Selenium to wait until the page loads after performing the particular action.

Accessors examine the state of the application and store the results in variables, e.g. “storeLocation”.

Assertions are like Accessors, but they verify that the state of the application conforms to what is expected

In this post we will see how to write Selenium Action command using a simple example.

Writing your first custom Selenium Action Command

In the following example we will add a new action, ‘typeRandomEmail’, which generates a random email address and types it in an input field.

Every Selenium Action command starts with a ‘do’ prefix. The corresponding action comprising ‘AndWait’ is automatically registered. e.g when we create the ‘typeRandomEmail’ action, the ‘typeRandomEmailAndWait’ command is automatically added to the command list. An action command takes up to two parameters, which will be passed the second and third column values in the test table. In our example we will be using only one parameter - the locator id where the random email will be typed.

The following shows the code for the typeRandomEmail action.

 
Selenium.prototype.doTypeRandomEmail = function(locator) {
    /**
    * Sets the value of an input field to a random email id, 
    * as though you typed it in.
    *
    * @param locator an <a href="#locators">element locator</a>
    */
 
    // All locator-strategies are automatically handled by "findElement"
    var element = this.page().findElement(locator);
 
    /* The following block generates a random email string */
    var allowedChars = "abcdefghiklmnopqrstuvwxyz";
    var stringLength = 8;
    var randomstring = '';
 
    for (var i=0; i<stringLength; i++) {
        var rnum = Math.floor(Math.random() * allowedChars.length);
        randomstring += allowedChars.substring(rnum,rnum+1);
    }
 
    // Append a domain name
    randomstring += "@somedomain.com"
 
    // Replace the element text with the new text
    this.browserbot.replaceText(element, randomstring);
};

Importing your custom commands in Selenium

Now that we have completed writing our own action command, it is time to import it to the Selenium IDE. Your custom commands are usually added to the file ‘user-extensions.js’. By default the ‘user-extensions.js’ file does not exist, so you need to first create a blank file into which you will add the above code. Once that is done you then need to tell Selenium to load the particular extension file from the ‘Options’ menu.

Once you have added the file to the options page you need to restart the Selenium IDE for the changes to take effect.

Whenever you add some new code or make changes to the exiting one in the ‘user-extensions.js’, you need to restart the Selenium IDE for the changes to take effect.

Now once you have restarted the IDE, you can see that your command has been added to the drop-down.

Writing other Action commands

You may be wondering how to go about writing other Selenium Action commands; what the this.browserbot object means and where it is defined. Although no clear documentation exists, the Selenium source code can itself be a valuable tool. All the Selenium commands are stored in the ’selenium-api.js’ file. I have included it here for easy download and reference. The original source file and other support files are located in the ’selenium-ide.jar’ file in your Selenium installation directory. Unzip that file and you have all the Selenium source code at your disposal.