Add avatar URL to Webfinger when available

spec/requests/webfinger_spec.rb

@@ -18,6 +18,46 @@ RSpec.describe "WebFinger", type: :request do
       })
     end
 
+    describe "Avatar" do
+      context "not available" do
+        it "does not include an avatar link" do
+          get "/.well-known/webfinger?resource=acct%3Atony%40kosmos.org"
+          expect(response).to have_http_status(:ok)
+          res = JSON.parse(response.body)
+
+          link = res["links"].find{|l| l["rel"] == "http://webfinger.net/rel/avatar"}
+          expect(link).to be_nil
+        end
+      end
+
+      context "available" do
+        let(:fixture_path) { Rails.root.join("spec/fixtures/files/taipei.jpg") }
+        let(:img_data) { File.read(fixture_path) }
+        let(:img_hash) { Digest::SHA256.hexdigest(img_data) }
+
+        before do
+          ActiveStorage::Blob.create_and_upload!(
+            io: File.open(fixture_path),
+            filename: "#{img_hash}.jpg",
+            content_type: "image/jpeg"
+          ).tap do |blob|
+            user.avatar.attach(blob)
+          end
+        end
+
+        it "includes a public avatar link" do
+          get "/.well-known/webfinger?resource=acct%3Atony%40kosmos.org"
+          expect(response).to have_http_status(:ok)
+          res = JSON.parse(response.body)
+
+          link = res["links"].find { |l| l["rel"] == "http://webfinger.net/rel/avatar" }
+          expect(link).to be_present
+          expect(link["type"]).to eq("image/jpeg")
+          expect(link["href"]).to match(%r{users/tony/avatars/#{img_hash}.jpg})
+        end
+      end
+    end
+
     describe "Mastodon entries" do
       context "Mastodon available" do
         it "includes the Mastodon aliases and links for the user" do