How to use xpath in Selenium RC with JavaScript?

Question

I am using Selenium RC with IE 6 and XPath locators are terribly slow. So I am trying to see if javascript-xpath actually speeds up things.

But could not find enough/clear documentation on how to use native x- path libraries.

I am doing the following:

protected void startSelenium (String testServer, String appName, String testInBrowser){
    selenium = new DefaultSelenium("localhost", 4444, "*" +testInBrowser, testServer+ "/"+ appName + "/");
    echo("selenium instance created:"+selenium.getClass());
    selenium.start();
    echo("selenium instance started..." + testServer + "/" + appName +"/");

    selenium.runScript("lib/javascript-xpath-latest-cmp.js");
    selenium.useXpathLibrary("javascript-xpath");
    selenium.allowNativeXpath("true");
}

This results in speed improvement of XPath locator but the improvements are not consistent. On some runs the time taken for a locator is halved; while sometimes its randomly high.

Am I missing any configuration step here? Would be great if someone who has had success with this could share their views and approach.

Thanks, Nirmal

Solution:

protected void startSelenium (String testServer, String appName, String testInBrowser){
    selenium = new DefaultSelenium("localhost", 4444, "*" +testInBrowser, testServer+ "/"+ appName + "/");
    echo("selenium instance created:"+selenium.getClass());
    selenium.start();
    echo("selenium instance started..." + testServer + "/" + appName +"/");

    selenium.useXpathLibrary("javascript-xpath");
}

score 4 · Accepted Answer · answered Mar 29 '10 at 20:30

4

I implemented this myself and I only had to do selenium.useXpathLibrary("javascript-xpath"). In my tests, the javascript xpath was about 7x faster on IE 8. Haven't really tested on anything else, but we only use it for IE.

answered Mar 29 '10 at 20:30

Dan at Demand

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Hi Dan, If we do not explicitly add the script; where does the engine come from?? Does selenium already include this js?? i wasnt able to find any such evidence. – Nirmal Patel Mar 30 '10 at 05:55
If you look at the Selenium source code, you'll see javascript-xpath-0.1.11.js is include in common\src\js\core\xpath, so I'm assuming it's pulling from that. SOMETHING is resulting in my tests going 7x faster. =) – Dan at Demand Mar 30 '10 at 22:02

score 0 · Answer 2 · answered Mar 29 '10 at 19:43

I have never done this but think that you may need to do something like

//Add the library to the page since runScript just does an eval on the JS
selenium.runScript("document.body.append(document.createElement('script')).src = 'path/to/lib');"); 
selenium.useXpathLibrary("javascript-xpath");
selenium.allowNativeXpath("true");

You will need to add the library to the page and then load it.

However, I would recommend using CSS Selectors instead of XPath Selectors as they are a lot faster in Selenium. You can see how to use different locator strategies here. I have seen tests become at least twice as fast as the original XPath.

I am currently using CSS Selectors... but they are a bit more complicated and there are more problems when using them with IE. Am exploring the speed improvements offered by javascript-xpath to see it they compare with CSS selectors. — Nirmal Patel, Mar 30 '10 at 05:40

How to use xpath in Selenium RC with JavaScript?

2 Answers2