ZK Testing with Selenium IDE

Author
Robert Wenzel, Engineer, Potix Corporation

Date
July 2013

Version
ZK 6.5 (or later)

This page is under construction, so we cannot guarantee the accuracy of the content!

Introduction

About this article

nice application, how to test ... refer to zats... some things need to be tested in a real browser, so selenium comes into play... how to create tests

programmatically... link to older Small Talk?? or use Selenium-IDE to record/tweak/maintain!! and replay/debug -- this article :D

Environment

• Firefox (used with 21.0)
• Selenium IDE 2.0.0
• JDK 6/7
• ZK 6.5.3 6/7
• Maven 3.0

Steps

Initialize your testing environment

• download Selenium IDE 2.0.0 link
  • docu http://wiki.openqa.org/display/SIDE/Home
• Maven 3.0
  • download link
  • setup maven

• download link (test project)
• maven: mvn jetty:run
• localhost:8080

(- war file ) ???

Initial Situation

1. Launch Selenium IDE CTRL+ALT+S
2. open example app localhost:8080
3. Record login-test and replay it

New Test
open	/selenium_testing/login.zul
type	id=jXDW5	test
type	id=jXDW8	test
clickAndWait	id=jXDWb

Looks hard to read / maintain and doesn't even work :'(

Looking at the recorded commands and comparing with page source we notice the IDs are generated and changing with every request. So no chance to record / replay this way.

A way to make the IDs predictable is shown in the next Section.

Custom Id Generator

As mentioned in other Small Talks about testing one strategy is to use a custom IdGenerator implementation to create predictable, readable (with a business meaning) and easily selectable (by selenium) component ids.

public class TestingIdGenerator implements IdGenerator {

	public String nextComponentUuid(Desktop desktop, Component comp,
			ComponentInfo compInfo) {
        int i = Integer.parseInt(desktop.getAttribute("Id_Num").toString());
        i++;// Start from 1
        
        StringBuilder uuid = new StringBuilder("");
        
        desktop.setAttribute("Id_Num", String.valueOf(i));
        if(compInfo != null) {
        	String id = getId(compInfo);
        	if(id != null) {
        		uuid.append(id).append("_");
        	}
        	String tag = compInfo.getTag();
        	if(tag != null) {
        		uuid.append(tag).append("_");
        	}
        }
        return uuid.length() == 0 ? "zkcomp_" + i : uuid.append(i).toString();
    }

The IDs will look like this:

• {id}_{tag}_{##} (for components with a given id)
• {tag}_{##} (for components without a given id - e.g. listitems in a listbox)
• {zkcomp}_{##} (for other cases, just to make them unique)

e.g. a button in zul-file

<button id="login" label="login" />

will become something like this in HTML in browser (number can vary):

<button id="login_button_12" class="z-button-os" type="button">login</button>

In order to separate production from test configuration we can include an additional config file at startup to enable the TestingIdGenerator only for testing. In ZK this is possible by setting the library property org.zkoss.zk.config.path (also refer to our Testing Tips)

e.g. via VM argument -Dorg.zkoss.zk.config.path=/WEB-INF/zk-test.xml

Windows:

set MAVEN_OPTS=-Dorg.zkoss.zk.config.path=/WEB-INF/zk-test.xml
mvn jetty:run

Linux:

export MAVEN_OPTS=-Dorg.zkoss.zk.config.path=/WEB-INF/zk-test.xml
mvn jetty:run

TODO: improve using maven profiles...

Now we get nicer and deterministic IDs when recording a test case.

After recording login-test again and we get this:

login test
open	/selenium_testing/login.zul
type	id=username_textbox_6	test
type	id=password_textbox_9	test
clickAndWait	id=login_button_12

This already looks nice, and self explaining - Unfortunately still fails to replay :(

Why this happens and how to fix it? See next section ...

ZK specific details

ZK heavily uses JavaScript and Selenium IDE does not record all events by default.

in our case here the "blur" events of the input fields have not been recorded, but ZK relies on them to determine updated fields. So we need to manually add selenium commands "fireEvent target blur" unfortunately Selenium does not offer a nice equivalent like "focus" action.

login test
open	/selenium_testing/login.zul
type	id=username_textbox_6	test
fireEvent	id=username_textbox_6	blur
type	id=password_textbox_9	test
fireEvent	id=password_textbox_9	blur
clickAndWait	id=login_button_12
assertLocation	glob:*/selenium_testing/index.zul
verifyTextPresent	Welcome test
verifyTextPresent	Feedback Overview

Replaying the script finally works :D, and we see the overview page (also added a few verifications for that).

Selenium Extensions

If you find the syntax of "fireEvent" hard to remember or think it is too inconvenient to add an additional line just to update an input field there's help using a Selenium Core extension. The extension - file usually called user-extensions.js and can be used in both Selenium-IDE and Selenium RC when running the tests outside of Selenium IDE (please refer to [selenium documentation]).

This snippet shows 2 simple custom actions:

blur

convenience action to avoid "fireEvent locator blur"

typeAndBlur

combines the type with a blur event, to make ZK aware of the input change automatically

Selenium.prototype.doBlur = function(locator) {
    // All locator-strategies are automatically handled by "findElement"
    var element = this.page().findElement(locator);
    // Fire the "blur" event
    triggerEvent(element, "blur", false);
};

Selenium.prototype.doTypeAndBlur = function(locator, text) {
    // All locator-strategies are automatically handled by "findElement"
    var element = this.page().findElement(locator);

    // Replace the element text with the new text
    this.page().replaceText(element, text);
    // Fire the "blur" event
    triggerEvent(element, "blur", false);
};

To enable it just download the example file, and add it to the Selenium-IDE configuration. (the file contains another extension ... more about that later in "making tests more robust and maintainable to UI updates")

(Selenium-IDE Options > Options... > [General -Tab] > Selenium Core extensions)

Then restart Selenium-IDE - close the window, and reopen it - e.g. by [CTRL+ALT+S]

Adapted test using the blur action:

login test
open	/selenium_testing/login.zul
type	id=username_textbox_6	test
blur	id=username_textbox_6
type	id=password_textbox_9	test
blur	id=password_textbox_9
clickAndWait	id=login_button_12

Same test using the typeAndBlur:

login test
open	/selenium_testing/login.zul
typeAndBlur	id=username_textbox_6	test
typeAndBlur	id=password_textbox_9	test
clickAndWait	id=login_button_12

It is not required to use either of these extensions, but saving 1 line for each input is my personal preference.

Another thing to keep in mind is robustness and maintenance effort of test-cases when changes in the UI happen ... the generated numbers in the end of each ID are still an obstacle on this way as they are prone to change everytime a component is added or removed above that component.

Wouldn't it be nice to avoid having to adapt test cases that often? Read on...

Improve robustness and maintainability of Test Scripts

Locators in Selenium

To remove the hard coded running numbers of the component IDs from our test cases Selenium offers e.g. XPath or CSS locators.

Using XPath is it possible to select a node by its ID-prefix:

//input[starts-with(@id, 'username_')]

This will work as long as the prefix "username_" is unique on the page, otherwise will perform the action on the first element found. So it is a good idea for this scenario to give widgets suitable IDs (plus: it will also improve the readability of source code).

In more complex cases one can select nested components to distinguish components with the same ID (e.g. in different ID spaces). e.g. if the "street" component appears several times on the page use this:

//div[starts-with(@id, 'deliveryAddress_')]//input[starts-with(@id, 'street_')]
//div[starts-with(@id, 'billingAddress_')]//input[starts-with(@id, 'street_')]

Another example using locating the delete button in the currently selected row of a listbox using ID prefixes, CSS-class and text comparison.

//div[starts-with(@id, 'overviewList_')]//tr[contains(@class, 'z-listitem-seld')]//button[text() = 'delete']

NOTE: Make sure not too use the "//" operator too extensively in XPath, as it might perform badly. (for me this was never a matter sofar, as there are much worse performance bottle necks, affecting your test execution speed - improve test execution speed).

This sheet provided by Michael Sorens is an excellent reference with many helpful examples how to select page elements in various situations.

So now we can change the test case to use this kind of XPath locator, searching only by ID prefix:

login test
open	/selenium_testing/login.zul
typeAndBlur	//input[starts-with(@id, 'username_')]	test
typeAndBlur	//input[starts-with(@id, 'password_')]	test
clickAndWait	//button[starts-with(@id, 'login_')]

Done that, the order of the components may change without breaking the test, as long as the actual IDs are not changed. Of course this requires some manual work, but the effort invested once will pay off quickly as your project evolves.

Custom Locator and LocatorBuilder

If you don't want to change the locator to XPath manually everytime after you recorded a test case Selenium IDE has more to offer. Even improving the readability.

Custom Locator

In the user-extensions.js from above you'll find a custom locator that will hide the XPath complexity for simple locate scenarios. It is based on the format of IDs generated by TestingIdGenerator (from above).

// The "inDocument" is a the document you are searching.
PageBot.prototype.locateElementByZkTest = function(text, inDocument) {
    // Create the text to search for
	
    var text2 = text.trim();

	var separatorIndex = text2.indexOf(" ");
	
	var elementNameAndIdPrefix = (separatorIndex != -1 ? text2.substring(0, separatorIndex) : text2).split("#");
	var xpathSuffix = separatorIndex != -1 ? text2.substring(separatorIndex + 1) : "";
	
	var elementName = elementNameAndIdPrefix[0] || "*";
	var idPrefix = elementNameAndIdPrefix[1];

	var xpath = "//" + elementName + "[starts-with(@id, '" + idPrefix + "')]" + xpathSuffix;

    return this.xpathEvaluator.selectSingleNode(inDocument, xpath, null, this._namespaceResolver);
};

this locator will work in 2 forms

1. zktest=#login_
2. zktest=input#username_

Internally generated/queried XPaths will be

1. //*[starts-with(@id, 'login_')]
2. //input[starts-with(@id, 'username_')]

1. will look for any element with an ID starting with "login_"
2. will also test the elements html tag, and find the <input> element with the ID-prefix "username_..."

Custom LocatorBuilder

Now to make this really handy Selenium IDE also offers extensions (don't mix this up with Selenium Core Extension)

Add file zktest-Selenium-IDE-extension.js to selenium config

(Selenium IDE Options > Options... > [General -Tab] > Selenium IDE extensions)

and move it up in the Locator Builder priority list.

(Selenium IDE Options > Options... > [Locator Builders - Tab])

It contains the following LocatorBuilder which will generate the locator in form "zktest=elementTag#IdPrefix" mentioned above using only the first part of the ID (the ID prefix - its business name). If an ID does not contain 3 tokens separated by "_" it will use the full ID instead including the sequential number, this will indicate to you that the element has no ID specified and another location approach is maybe better, or just give it an ID in the zul file.

 
LocatorBuilders.add('zktest', function(e) {
	var idTokens = e.id.split("_")
	if (idTokens.length > 2) {
		idTokens.pop();
		idTokens.pop();
		return "zktest=" + e.nodeName.toLowerCase() + "#" + idTokens.join("_") + "_";
	} else {
		return "zktest=" + "#" + e.id;
	}
	return null;
});

Restart Selenium-IDE and record the test case again... and you'll get this (after changing the "type" to "typeAndBlur" events).

New Test
open	/selenium_testing/login.zul
typeAndBlur	zktest=input#username_	test
typeAndBlur	zktest=input#password_	test
clickAndWait	zktest=button#login_

bigger test

Let's record a test case for edit and save an existing "feedback item" in the list, and verify the results, and a logout test.