Validate even when there are no rows
Validate even when there are no rows

We have an error case for EMPTY_FILE, but it was impossible to reach this
case because if the reader object did not iterate once, the file level
validations were not executed.

clever-crow-consulting/otm-core,recklessromeo/otm-core,RickMohr/otm-core,clever-crow-consulting/otm-core,maurizi/otm-core,clever-crow-consulting/otm-core,RickMohr/otm-core,maurizi/otm-core,recklessromeo/otm-core,RickMohr/otm-core,maurizi/otm-core,maurizi/otm-core,recklessromeo/otm-core,recklessromeo/otm-core,clever-crow-consulting/otm-core,RickMohr/otm-core