TEST :model groups (ALL) : all can only be root
http://www.w3.org/TR/2004/REC-xmlschema-1-20041028/#Model_Groups
| Item | Value | 
|---|---|
| title | mgA020 - mgA020 | 
| name | mgA020 | 
| source | ../mgA020.xsd | 
| schemaName | ../mgA020.xsd | 
| keywords | schema negative | 
| package | javasoft.sqe.tests.modelgroups.mga020 |