I've written a custom migrate module in Drupal 8. (Based on these instructions: https://github.com/wunderkraut/migrate_source_example/)
The migration reads data from a XML file with the "migrate_source_xml" extension and should write/update the data in a node.
I have a yml config file in /config/install/ and some logic in /src/migrate/source/
When I run the migration with "drush mi --all" I get the correct values in my prepareRow function. Unfortunately, no nodes were create and I get the message "Processed 0 items (0 created, 0 updated, 0 failed, 0 ignored)"
With the prepareRow function I'm able to stop the script at this position. But how can I debug the script afterwards? Does exist a postImport function or something similar?
How do you test your D8 migrations?
Thank you very much for your inputs!