Groovier Selenium (Djug)

Groovier Selenium
Denver JUG 8/13/2008
Frederic Jean
fred@fredjean.net
frederic.jean@sun.com

Wednesday, August 13, 2008 1

who am i


Topics
(Really) Quick intro to Selenium
Groovy Metaprogramming through
progressive refactorings of a single,
simple yet verbose Java Selenium RC
Driver example.
A few sundry items


Selenium

UI testing tool
Runs in browser
Well suited for Ajax applications


Selenium IDE

Firefox plugin
Simpliﬁes writing and testing Selenese
test case
Can record and play back Selenese tests


Selenese
HTML Tables
Action
Target
Value
Intepreted by Selenium Core
Actions match JavaScript functions


Example
BlogTest

open /

clickAndWait link=Adoption

Out of my mind... : category
assertTitle
adoption


Selenese Locators

Allows an action to target a speciﬁc
DOM element on the page
<type>=<locator>


Selenese Locators
Locator Type Description
The name of an input element on a
name
form
The id associated with an element
id
on a page
The text contained within an anchor
link
element (<a/>)
A JavaScript expression that
dom
returns an element
An XPath expression pointing to an
xpath
element on the page


Sample Test


Selenese TestSuites

Groups and organizes individual
Selenese tests
Can be run through ant


Selenium RC

Runs as a process on a system
Listens to requests on a speciﬁc port
Has drivers for different languages


Selenium RC Drivers
Drives the Selenium RC Ser ver
programatically
Allows integration with xUnit
frameworks
Flow control and conditionals
Java driver provides a SeleneseTestCase
class


Generating Java Test


Generated Java
package com.example.tests;

import com.thoughtworks.selenium.*;
import java.util.regex.Pattern;

public class NewTest extends SeleneseTestCase {
public void setUp() throws Exception {
setUp(quot;http://fredjean.net/quot;, quot;*chromequot;);
}
public void testNew() throws Exception {
selenium.open(quot;/quot;);
selenium.click(quot;link=Adoptionquot;);
selenium.waitForPageToLoad(quot;30000quot;);
assertEquals(quot;Out of my mind... : category adoptionquot;, selenium.getTitle());
selenium.click(quot;link=We Are Out!quot;);
for (int second = 0;; second++) {
if (second >= 60) fail(quot;timeoutquot;);
try { if (selenium.isTextPresent(quot;Commentsquot;)) break; } catch (Exception e) {}
Thread.sleep(1000);
}

assertTrue(selenium.isTextPresent(quot;Trackbacksquot;));
}
}


Generated Java
Where

is it used?

}
Thread.sleep(1000);
}

}
}


Generated Java

import com.thoughtworks.selenium.*; Need to rename class.

}
Thread.sleep(1000);
}

}
}


Generated Java from
Must inherit
SeleneseTestCase


}
Thread.sleep(1000);
}

}
}


Generated Java


Should rename method
}
Thread.sleep(1000);
}

}
}


Generated Java

selenium.this

selenium.that

} selenium.thisandthat

Thread.sleep(1000);
}

}
}


Generated Java


}
public void testNew() throws Exception { Where did
waitForTextPresent go?
Thread.sleep(1000);
}

}
}


Generated Java

Good start
Needs some work to be useful
Certainly faster than coding by hand
Noisy


Groovy
package com.example.tests

import com.thoughtworks.selenium.*

class NewGroovyTest extends SeleneseTestCase {
void setUp() {
setUp quot;http://fredjean.net/quot;, quot;*chromequot;
}
void testNew() {
selenium.open quot;/quot;
selenium.click quot;link=Adoptionquot;
selenium.waitForPageToLoad quot;30000quot;
assert quot;Out of my mind... : category adoptionquot; == selenium.title
selenium.click quot;link=We Are Out!quot;
for (second in 0..60) {
if (second == 60) fail quot;timeoutquot;
if (selenium.isTextPresent(quot;Commentsquot;)) break;
sleep(1000)
}

assert selenium.isTextPresent(quot;Trackbacksquot;)
}
}


Groovy

Less noisy than Java
Still repetitive
waitForTextPresent is still missing


Metaprogramming

Writing of computer programs that write or
manipulate other programs (or themselves) as
their data.

http://en.wikipedia.org/wiki/Metaprogramming

Metaprogramming

Increases code expressiveness
Allows SMEs to understand the code
Domain Speciﬁc Languages


Meta Object Protocol
Establishes the rules behind method
calling in Groovy
Provides the hooks to modify your
program's behavior
invokeMethod
propertyMissing
methodMissing


Metaclass

All Groovy objects have one
Can be deﬁned for Java objects
Per class vs per instance
Allows developers to quot;mutatequot; a class


Delegation
For ward method calls to another object
Tedious to do in Java
Extend delegate
Manually code delegation code
Almost trivial in Groovy
ExpandoMetaClass


Groovy Delegation
/**
* Called when a method cannot be found in the class
* or the meta class for an object or class.
* @param name The name of the missing method
* @param args The arguments for the method
*/
void methodMissing(String name, args) {
selenium.quot;$namequot;(* args)
}

/**
* Called when a property cannot be found in the class
* or the meta class associated with a class or object.
* @param name The name of the property
*/
void propertyMissing(String name) {
selenium.quot;$namequot;
}


Goodbye Repetition
void testDelegation() {
open quot;/quot;
click quot;link=Adoptionquot;
waitForPageToLoad quot;30000quot;
assert quot;Out of my mind... : category adoptionquot; == title
click quot;link=We Are Out!quot;
if (isTextPresent(quot;Commentsquot;)) break;
sleep(1000)
}

assert isTextPresent(quot;Trackbacksquot;)
}


Performance Hit


Intercept, Cache, Invoke

/**
* Called when a method cannot be found in the class
* or the meta class for an object or class.
* @param name The name of the missing method
* @param args The arguments for the method
*/
void methodMissing(String name, args) {
NewGroovyTest.metaClass.quot;$namequot; = { Object varArgs ->
delegate.selenium.metaClass.invokeMethod(delegate.selenium, name, varArgs)
}
selenium.quot;$namequot;(* args)
}


Performance Hit


Groovy Delegation

Results in cleaner test code
Almost trivial to implement in Groovy
Performance hit can be mitigated


waitForTextPresent?
open quot;/quot;
sleep(1000)
}

}


waitForTextPresent?
open quot;/quot; Replaces waitFor...
waitForPageToLoad quot;30000quot; with a loop
sleep(1000)
}

}


waitForTextPresent?
open quot;/quot;
How about

assertTextPresent?
sleep(1000)
}

}


waitForTextPresent?

Selenese generates waitFor, verify, and
assert methods
Java driver doesn't provide them
Java -> Explicitly typed language
JavaScript -> What's a type?


Wait a minute...

JavaScript is a dynamic language...
Groovy is a dynamic language...
Why not synthesize these methods in
Groovy?


Synthetic Methods

Methods that don't really exist
Grails ﬁnder methods
Person.findByFirstNameAndAge(...)


Steps to Take

Identify synthetic methods
Implement behavior
Locate actual getter method


Identifying Methods
def methodMissing(String name, args) {
switch (name) {
case ~/waitForNot.*/: return waitForNot(name, args)
case ~/waitFor.*/: return waitFor(name, args)
case ~/assertNot.*/:
assertNot(name, args)
break
case ~/assert.*/:
assertThat(name, args)
break
case ~/verifyNot.*/:
return verifyNot(name, args)
case ~/verify.*/:
return verifyThat(name, args)
default:
return createAndCallMethod(name, args)
}
}


Implement Behavior
private waitFor(name, args) {
// Make the bold assumption that the time out is the first param.
def timeout = args[0]
if (timeout instanceof Integer) {
args = args[1..args.length - 1].toArray()
} else {
timeout = 60000
}
def methodName = getMethodName(quot;waitForquot;, name);
for (i in 0..(timeout / 1000)) {
if (quot;$methodNamequot;(* args)) {
return true;
}
sleep(1000)
}
fail(quot;Timeout occured in $name for $argsquot;)
}


Locating Getter

def getMethodName(prefix, name) {
[quot;isquot;, quot;getquot;].collect {
name.replaceFirst(prefix, it)
}.find {
delegate.selenium.metaClass.respondsTo(delegate.selenium, it)
}
}


Loop Begone!

open quot;/quot;
waitForTextPresent quot;Commentsquot;
assertTextPresent quot;Trackbacksquot;
}


Refactor!
Move methods to super class
methodMissing
propertyMissing
Supporting methods
Group Groovy tests in one suite


GroovierSelenium
Extends SeleneseTestCase with
methodMissing
Allows Groovy users to write tests that
almost look like Selenese
http://groovierselenium.googlecode.com
Licensed under ASLv2.0


Near Future

JUnit 4.5 test runners
GroovierSeleniumRunner
GroovySuiteRunner
@Selenium annotation


NetBeans & Groovy

Grails and Groovy Plugin integrated
with NetBeans 6.5
Adds Groovy Support to Java Projects


Looking Back
Talked about Selenium
Leveraging Groovy metaprogramming
Delegating to another object
Creating synthetic methods
GroovierSelenium
NetBeans


Book

Programming Groovy (Venkat S.)


Links

http://groovy.codehaus.org
http://groovierselenium.googlecode.com
http://www.pragprog.com/titles/vslg/
programming-groovy


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