suggestion: validator check for empty XML elements

[hacklsn]

Recently I stumbled upon an empty <ProviderName/> element in a ServiceList. It actually caused the the DVB-I ref-app to crash with un uncaught type error. Could be a useful addition to the validator to check for empty elements - at least mandatory ones - in the shape of <tag/> or <tag></tag>

[paulhiggs]

This can certainly be added to the validator, but another option would be to add a minimum length in the schema itself.