Yup, as I said, I’ve left an “issue” on the github project.
I just tried to import a test CSV with the following:
client_id,invoice_number,paid,invoice_date,due_date,product,amount,quantity
1,111111,220.00,2016-04-22,2016-05-22,,,
1,111111,220.00,2016-04-22,2016-05-22,"1a2hx4",220.00,1
The previewer on the import screen said it would create 2 invoices, however I continued anyway, just to see what would actually happen:
The following records failed to import, they either already exist or are missing required fields.
{"name":"1","invoice_number":"111111","po_number":false,"invoice_date":"2016-04-22","due_date":"2016-05-22","amount":"","paid":"220.00","notes":false,"terms":false,"product":"","quantity":""}
{"name":"1","invoice_number":"111111","po_number":false,"invoice_date":"2016-04-22","due_date":"2016-05-22","amount":"220.00","paid":"220.00","notes":false,"terms":false,"product":"1a2hx4","quantity":"1"}
I exported a CSV from Invoice Ninja to see if it would provide any insights, however it seems IN only exports invoice totals, without item breakdowns.