2429 allow transcribers to delete subjects

[symmetrically]

No description provided.

[benwbrum]

There are a couple of changes in functionality relating to project owners versus subject creators

[benwbrum]

The test suite is failing with a foreign key check which seems related to the work done here. I'm re-starting it to see if this is just an artifact of TravisCI or a real regression.

[benwbrum]

We are consistently getting this exception in the test suite:

  1) XmlSourceProcessor#wiki_to_xml subject linking not disabled (default) builds the xml document
     Failure/Error: article.save! unless preview_mode
     
     ActiveRecord::InvalidForeignKey:
       Mysql2::Error: Cannot add or update a child row: a foreign key constraint fails (`diary_test`.`articles`, CONSTRAINT `fk_rails_35e2f292e3` FOREIGN KEY (`created_by_id`) REFERENCES `users` (`id`))
     # ./app/models/xml_source_processor.rb:373:in `block in update_links_and_xml'
     # ./app/models/xml_source_processor.rb:353:in `update_links_and_xml'
     # ./app/models/xml_source_processor.rb:114:in `wiki_to_xml'
     # ./spec/models/xml_source_processor_spec.rb:41:in `block (4 levels) in <top (required)>'
     # ------------------
     # --- Caused by: ---
     # Mysql2::Error:
     #   Cannot add or update a child row: a foreign key constraint fails (`diary_test`.`articles`, CONSTRAINT `fk_rails_35e2f292e3` FOREIGN KEY (`created_by_id`) REFERENCES `users` (`id`))
     #   ./app/models/xml_source_processor.rb:373:in `block in update_links_and_xml'

The failure happens on line 39 of the XML Source processor spec, which is before the actual test runs, indicating that the problem may be with the fixture or factory data. Could it be that we need to include a user reference in the article factory constructor?

[benwbrum]

The test failure here seems to be due to code in xml_source_processor.rb which sets the article's user relation to the value of User.current_user. When the test fails, the value of User.current_user.id is 4, but there is no record in the users table with an ID of 4 -- only 1 and 2 exist.

DB foreign keys were introduced in later versions of Rails than those current when the most of the xml_source_processor.rb functionality was written -- as a result, models like Page and PageVersion can have their users set to values which may not be present in the database and tests don't fail.

I think we have a couple of options here:

• Remove the foreign key from the Article table. (I'm not a fan of this, but it would parallel the other tests and older models.
• Research foreign key constraints and the tools we're using for creating test data in this test. (Mocks? Factories?) Surely we are not the first developers to run into this problem, and there might just be a configuration option or something we can change.