Resolve unknown status from Add activity, skip Remove if unknown (#7526)

Fix #7518

spec/lib/activitypub/activity/add_spec.rb

@@ -18,12 +18,31 @@ RSpec.describe ActivityPub::Activity::Add do
   describe '#perform' do
     subject { described_class.new(json, sender) }
 
-    before do
+    it 'creates a pin' do
       subject.perform
+      expect(sender.pinned?(status)).to be true
     end
 
-    it 'creates a pin' do
-      expect(sender.pinned?(status)).to be true
+    context 'when status was not known before' do
+      let(:json) do
+        {
+          '@context': 'https://www.w3.org/ns/activitystreams',
+          id: 'foo',
+          type: 'Add',
+          actor: ActivityPub::TagManager.instance.uri_for(sender),
+          object: 'https://example.com/unknown',
+          target: sender.featured_collection_url,
+        }.with_indifferent_access
+      end
+
+      before do
+        stub_request(:get, 'https://example.com/unknown').to_return(status: 410)
+      end
+
+      it 'fetches the status' do
+        subject.perform
+        expect(a_request(:get, 'https://example.com/unknown')).to have_been_made.at_least_once
+      end
     end
   end
 end