The test checks the "ns" attribute with static strings.

>>>>templates/test.tpl
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<opt:root>
<foo>
<opt:attribute str:ns="foo" str:name="abc" str:value="def" />
bar
</foo>
</opt:root>

>>>>expected.txt
OUTPUT

>>>>result.txt
<foo foo:abc="def">
bar
</foo>