[xml] libxml schema validation - conflict result on attribute validation

["Phuong Nguyen" <shdwstar gmail com>]

I'm trying libxml on a very simple same file and got some rather
conflicting result. I'm still learning schema and libxml so any tip is
much appreciated.

Thanks.

result:
correct/test.xml:2: element sample: Schemas validity error : Element
'{http://www.test.com}sample', attribute 'abc': The attribute 'abc' is
not allowed.
correct/test.xml:2: element sample: Schemas validity error : Element
'{http://www.test.com}sample': The attribute
'{http://www.test.com}abc' is required but missing.
correct/test.xml fails to validate


xsd:
<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
targetNamespace="http://www.test.com"; elementFormDefault="qualified"
xmlns ="http://www.test.com";>

<xs:attribute name="abc" type="xs:integer"/>
<xs:element name="sample">
   <xs:complexType>
       <xs:sequence>
               <xs:element name="test"/>
       </xs:sequence>
       <xs:attribute ref="abc" use="required"/>
   </xs:complexType>
</xs:element>
</xs:schema>


xml:
<?xml version="1.0" encoding="ISO-8859-1"?>
<sample xmlns="http://www.test.com";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; abc="23">
<test/>
</sample>