I am trying to migrate some data with the migrate api in a custom entity called Seller.
Each seller has an email address with a constraint "UniqueField" which checks, that the email address is just entered once. If i try to import a seller with an existing email address, the seller will be created although the email already exists.
So my question is: Doesn't the migration api consider the entity validation or how can I do this?
One solution for the problem would be to write a custom process plugin for the email address, but it would be nice, if the entity validation would check this automatically.