Ensure DOI can be minted when only non-SEEK creators are present

lib/seek/doi/acts_as_doi_mintable.rb

@@ -43,7 +43,7 @@ def mint_doi
             return false
           end
 
-          if creators.empty?
+          if (respond_to?(:assets_creators) ? assets_creators : creators).empty?
             errors.add(:base, "At least one creator is required. To add, go to Actions -> Manage #{self.class.model_name.human}.")
             return false
           end

test/integration/doi_minting_test.rb

@@ -112,6 +112,7 @@ class DoiMintingTest < ActionDispatch::IntegrationTest
     asset.creators = []
     asset.save!
     assert_empty asset.creators
+    assert_empty asset.assets_creators
 
     post "/workflows/#{asset.id}/mint_doi"
     assert_redirected_to polymorphic_path(asset, version: asset.version)
@@ -120,6 +121,24 @@ class DoiMintingTest < ActionDispatch::IntegrationTest
     refute AssetDoiLog.was_doi_minted_for?(asset.class.name, asset.id, asset.version)
   end
 
+  test 'do not show error if non-SEEK creator present' do
+    mock_datacite_request
+    asset = FactoryBot.create(:workflow, policy: FactoryBot.create(:public_policy))
+    assert asset.is_published?
+    assert asset.can_manage?
+
+    asset.creators = []
+    asset.assets_creators.create!(given_name: 'Julia', family_name: 'Jones', orcid: 'https://orcid.org/0000-0001-8172-8981')
+    asset.save!
+    assert_empty asset.creators
+    assert_not_empty asset.assets_creators
+
+    post "/workflows/#{asset.id}/mint_doi"
+    assert_redirected_to polymorphic_path(asset, version: asset.version)
+    assert_not_nil flash[:notice]
+    assert AssetDoiLog.was_doi_minted_for?(asset.class.name, asset.id, asset.version)
+  end
+
   test 'handle error when mint_doi' do
     mock_datacite_request
     DOIABLE_ASSETS.each do |type|