Improved remote thread fetching (#10106)

* Fetch up to 5 replies when discovering a new remote status

This is used for resolving threads downwards. The originating
server must add a “replies” attributes with such replies for it to
be useful.

* Add some tests for ActivityPub::FetchRepliesWorker

* Add specs for ActivityPub::FetchRepliesService

* Serialize up to 5 public self-replies for ActivityPub notes

* Add specs for ActivityPub::NoteSerializer

* Move exponential backoff logic to a worker concern

* Fetch first page of paginated collections when fetching thread replies

* Add specs for paginated collections in replies

* Move Note replies serialization to a first CollectionPage

The collection isn't actually paginable yet as it has no id nor
a `next` field. This may come in another PR.

* Use pluck(:uri) instead of map(&:uri) to improve performances

* Fix fetching replies when they are in a CollectionPage

1 files changed, 44 insertions, 0 deletions

diff --git a/spec/serializers/activitypub/note_spec.rb b/spec/serializers/activitypub/note_spec.rb
new file mode 100644
index 000000000..55bfbc16b
--- /dev/null
+++ b/spec/serializers/activitypub/note_spec.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe ActivityPub::NoteSerializer do
+  let!(:account) { Fabricate(:account) }
+  let!(:other)   { Fabricate(:account) }
+  let!(:parent)  { Fabricate(:status, account: account, visibility: :public) }
+  let!(:reply1)  { Fabricate(:status, account: account, thread: parent, visibility: :public) }
+  let!(:reply2)  { Fabricate(:status, account: account, thread: parent, visibility: :public) }
+  let!(:reply3)  { Fabricate(:status, account: other, thread: parent, visibility: :public) }
+  let!(:reply4)  { Fabricate(:status, account: account, thread: parent, visibility: :public) }
+  let!(:reply5)  { Fabricate(:status, account: account, thread: parent, visibility: :direct) }
+
+  before(:each) do
+    @serialization = ActiveModelSerializers::SerializableResource.new(parent, serializer: ActivityPub::NoteSerializer, adapter: ActivityPub::Adapter)
+  end
+
+  subject { JSON.parse(@serialization.to_json) }
+
+  it 'has a Note type' do
+    expect(subject['type']).to eql('Note')
+  end
+
+  it 'has a replies collection' do
+    expect(subject['replies']['type']).to eql('Collection')
+  end
+
+  it 'has a replies collection with a first Page' do
+    expect(subject['replies']['first']['type']).to eql('CollectionPage')
+  end
+
+  it 'includes public self-replies in its replies collection' do
+    expect(subject['replies']['first']['items']).to include(reply1.uri, reply2.uri, reply4.uri)
+  end
+
+  it 'does not include replies from others in its replies collection' do
+    expect(subject['replies']['first']['items']).to_not include(reply3.uri)
+  end
+
+  it 'does not include replies with direct visibility in its replies collection' do
+    expect(subject['replies']['first']['items']).to_not include(reply5.uri)
+  end
+end