JUnit Test if XML Document is sorted on arbitrary column

Question

Given an xml document like

<root>
  <row>
    <a>2</a>
    <b>1</b>
    <c>8</c>
  </row>
  <row>
    <b>5</b>
    <a>2</a>
    <c>8</c>
  </row>
  <row>
    <a>2</a>
    <c>8</c>
    <b>6</b>
  </row>
</root>

Is there an easy way to assert that the XML document is sorted on element B in XMLUnit

Edit: I have an odd problem with a piece of software that I can not change where the value of the XML tags in any given node needs to be in a specific order. I'd like it for my test harness to enforce this set of rules before any other validation.

Answer 1

You can build an assertion around an XPath selection.

Probably the simplest way would be to use the XPath expression /root/row/b, request the NODESET result type, then copy the text from each result node into a List structure. You can assert that the text in that list is equal to an "expected" list created with the Arrays.asList() method (I'm assuming you're using Java).

Answer 2

If you can execute XQuery, then the XQuery assertion:

every $i in (1 to count ($x/row) - 1)
satisfies 
   let $j :=  $i + 1   
   return number($x/row[$i]/b) <= number($x/row[$j]/b)

where $x is the document, is true if the rows are in ascending order of b, false otherwise

Answer 3

Use the value of the following simple XPath 1.0 expression:

not(//b[. > following::b])