Make headline images explicit, add asset credits

- related_assets gains a `headline` boolean (DB-enforced: at most one
  per page), replacing "first image by position" as the headline
  rule. A rake task backfills the current first image on every live
  head/draft, so nothing changes visually until an editor changes it.
- The image picker sidebar gets a star toggle reflecting the flag;
  the TinyMCE inline-image picker's badge now reads it too, instead
  of assuming position 0.
- No headline chosen (or none attached) now falls back to the
  gallery-count caption itself becoming the lightbox trigger, instead
  of the gallery being unreachable.
- Assets gain creator, source_url, and license_key (against a new
  config/asset_licenses.yml dictionary). asset_credit renders a
  degrading attribution line, reused as a hidden per-image glightbox
  caption so credit is one click away for every image, not only the
  headline's always-visible one.
- Fixed: asset thumbnails rendered unconditionally regardless of
  whether a real variant exists on disk. Asset#has_variant? checks
  file existence, not content type -- some legacy PDFs have real
  pre-rewrite thumbnails a content-type check would have hidden.
- assets#new/edit rebuilt onto the same node_description/node_content
  layout as assets#show, picking up the three new fields in the
  process.

1 files changed, 40 insertions, 4 deletions

diff --git a/test/models/related_asset_test.rb b/test/models/related_asset_test.rb
index a739e6bb..710b4cc4 100644
--- a/test/models/related_asset_test.rb
+++ b/test/models/related_asset_test.rb
@@ -1,8 +1,44 @@
 require 'test_helper'
 
-class RelatedImageTest < ActiveSupport::TestCase
-  # Replace this with your real tests.
-  test "the truth" do
-    assert true
+class RelatedAssetTest < ActiveSupport::TestCase
+  test "headline can be set on an image asset" do
+    node = Node.root.children.create!(:slug => "related_asset_headline_image_test")
+    asset = Asset.create!(:name => "photo", :upload_content_type => "image/png")
+    node.draft.assets << asset
+    related = node.draft.related_assets.find_by(:asset_id => asset.id)
+
+    related.headline = true
+    assert related.valid?
+  end
+
+  test "headline cannot be set on a non-image asset" do
+    node = Node.root.children.create!(:slug => "related_asset_headline_pdf_test")
+    asset = Asset.create!(:name => "programme", :upload_content_type => "application/pdf")
+    node.draft.assets << asset
+    related = node.draft.related_assets.find_by(:asset_id => asset.id)
+
+    related.headline = true
+    assert_not related.valid?
+    assert_includes related.errors[:headline], "can only be set on image assets"
+  end
+
+  test "the headline validation does not raise when asset is missing" do
+    related = RelatedAsset.new(:headline => true)
+    assert_not related.valid?
+  end
+
+  test "at most one headline per page is enforced at the database level" do
+    node = Node.root.children.create!(:slug => "related_asset_headline_uniqueness_test")
+    first  = Asset.create!(:name => "first", :upload_content_type => "image/png")
+    second = Asset.create!(:name => "second", :upload_content_type => "image/png")
+    node.draft.assets << first
+    node.draft.assets << second
+
+    node.draft.related_assets.find_by(:asset_id => first.id).update!(:headline => true)
+    second_related = node.draft.related_assets.find_by(:asset_id => second.id)
+
+    assert_raises(ActiveRecord::RecordNotUnique) do
+      RelatedAsset.where(:id => second_related.id).update_all(:headline => true)
+    end
   end
 end