Create multiple files in XSLT

Question

Here's one way to do it:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0">

  <xsl:output method="text"/>
  <xsl:output method="html" indent="yes" name="html"/>

  <!-- There's no need for a for-each loop. Just match all the
       testruns that are immediate children of tests -->
  <xsl:template match="/tests/testrun">
    <xsl:variable name="filename"
                  select="concat('output1/',@run,'.html')" />
    <xsl:value-of select="$filename" />
    <xsl:result-document href="{$filename}" format="html">
      <html><body>
        <xsl:value-of select="@run"/>
        <!-- You need to adapt this to your specific needs. -->
        <xsl:apply-templates select="test"/>
        <xsl:apply-templates select="testrun"/>
      </body></html>
    </xsl:result-document>
  </xsl:template>

  <!-- These templates are here mostly for illustration
       purposes. You'd have to decide that you actually want to do
       with your data. -->
  <xsl:template match="test">
    <p>test: <xsl:value-of select="@name"/></p>
  </xsl:template>

  <xsl:template match="testrun/testrun">
    <p>testrun: <xsl:value-of select="@run"/></p>
    <xsl:apply-templates select="test"/>
  </xsl:template>
</xsl:stylesheet>

The output/test2.html file will contain:

<html>
   <body>test2
      <p>test: foo</p>
      <p>test: bar</p>
      <p>test: baz</p>
      <p>testrun: test2.1</p>
      <p>test: foo</p>
      <p>test: bar</p>
      <p>test: baz</p>
   </body>
</html>

(If you edit the tests in test2.1 to change the names so that they don't repeat those of test2, you'll be able to clearly see that the foo, bar, baz after test2.1 are those of test2.1.)