Re: [Xmlunit-general] Sequence and text difference confusion

[Stefan B. <bo...@ap...>]

Hi Jonathan

On 2010-12-14, Jonathan Foulkes wrote:

> I'm working on a project that involves producing visual diffs of XML
> files. A major requirement is that elements should be able to be
> re-ordered but will not display as different unless they are logically
> different. I thought that XMLUnit's Diff class would accomplish this
> using the similar() function, and built my application
> accordingly.

In general it does - as long as it compares the elements you want it to
compare.  Sometimes XMLUnit will need you help in order to know what is
important to your comparision and this help comes by an
<http://xmlunit.sourceforge.net/userguide/html/ar01s03.html#ElementQualifier>

> For example, I have two blocks of XML:
> <application-variable>
>   <name>database</name>
>   <protected>false</protected>
>   <value>SupportTracker</value>
> </application-variable>
> <application-variable>
>   <name>conserver</name>
>   <protected>false</protected>
>   <value>jonathanf-vm</value>
> </application-variable>

> and

> <application-variable>
>   <name>conserver</name>
>   <protected>false</protected>
>   <value>jonathanf-vm</value>
> </application-variable>
> <application-variable>
>   <name>database</name>
>   <protected>false</protected>
>   <value>SupportTracker</value>
> </application-variable>

By default XMLUnit will compare the first application-variable element
of either XML snippet with each other and they are identical (same name,
no attributes at all, same number of children) and the dive further down
the subtree rooted by this element.  Of course the name elements it sees
next are different.

What you want XMLUnit to do is to make it realize that it has to look at
the nested text of the "name" child element of the
"application-variable" element when it decides which subtrees to
compare.

Neither of the built-in ElementQualifiers will work for you, you will
have to write an implementation of your own - but that won't be too
difficult.  You could extend ElementNameQualifier and only intercept it
if the element's local name matches application-variable to inject you
own logic.

Stefan