Removed pending pry statement
Removed assets because they are now directly embedded into the tests
Reworked is_part_if test as a shared example
Add field test for "created"
Add field test for "creator"
Add field test for "classification"
Add field test for "description"
Add field test for "edition"
Add field test for "format"
Add field test for "identifier"
Added field test for "language"
Add field test for "title"
Add field test for "signature"
Add field test for "subject"
Add field test for "publisher"