Re: concatenate multiple attribute values and assign i

based on michael kay response or abels response if I do, the problem is
I get 4 outputs of testnode
i.e

<testnode att1="1,2,3,4" att2="a,b,c,d" />
<testnode att1="1,2,3,4" att2="a,b,c,d" />
<testnode att1="1,2,3,4" att2="a,b,c,d" />
<testnode att1="1,2,3,4" att2="a,b,c,d" />

I want it to output only once.
This is what I have done based on michaels response. The following is a
portion of the xslt file I have.

 <xsl:template match="//testnode">
   <testnode>
 ....