Add ActivityPub inbox (#4216)

* Add ActivityPub inbox

* Handle ActivityPub deletes

* Handle ActivityPub creates

* Handle ActivityPub announces

* Stubs for handling all activities that need to be handled

* Add ActivityPub actor resolving

* Handle conversation URI passing in ActivityPub

* Handle content language in ActivityPub

* Send accept header when fetching actor, handle JSON parse errors

* Test for ActivityPub::FetchRemoteAccountService

* Handle public key and icon/image when embedded/as array/as resolvable URI

* Implement ActivityPub::FetchRemoteStatusService

* Add stubs for more interactions

* Undo activities implemented

* Handle out of order activities

* Hook up ActivityPub to ResolveRemoteAccountService, handle
Update Account activities

* Add fragment IDs to all transient activity serializers

* Add tests and fixes

* Add stubs for missing tests

* Add more tests

* Add more tests

1 files changed, 99 insertions, 0 deletions

diff --git a/spec/lib/activitypub/tag_manager_spec.rb b/spec/lib/activitypub/tag_manager_spec.rb
new file mode 100644
index 000000000..8f7662e24
--- /dev/null
+++ b/spec/lib/activitypub/tag_manager_spec.rb
@@ -0,0 +1,99 @@
+require 'rails_helper'
+
+RSpec.describe ActivityPub::TagManager do
+  include RoutingHelper
+
+  subject { described_class.instance }
+
+  describe '#url_for' do
+    it 'returns a string' do
+      account = Fabricate(:account)
+      expect(subject.url_for(account)).to be_a String
+    end
+  end
+
+  describe '#uri_for' do
+    it 'returns a string' do
+      account = Fabricate(:account)
+      expect(subject.uri_for(account)).to be_a String
+    end
+  end
+
+  describe '#to' do
+    it 'returns public collection for public status' do
+      status = Fabricate(:status, visibility: :public)
+      expect(subject.to(status)).to eq ['https://www.w3.org/ns/activitystreams#Public']
+    end
+
+    it 'returns followers collection for unlisted status' do
+      status = Fabricate(:status, visibility: :unlisted)
+      expect(subject.to(status)).to eq [account_followers_url(status.account)]
+    end
+
+    it 'returns followers collection for private status' do
+      status = Fabricate(:status, visibility: :private)
+      expect(subject.to(status)).to eq [account_followers_url(status.account)]
+    end
+
+    it 'returns URIs of mentions for direct status' do
+      status    = Fabricate(:status, visibility: :direct)
+      mentioned = Fabricate(:account)
+      status.mentions.create(account: mentioned)
+      expect(subject.to(status)).to eq [subject.uri_for(mentioned)]
+    end
+  end
+
+  describe '#cc' do
+    it 'returns followers collection for public status' do
+      status = Fabricate(:status, visibility: :public)
+      expect(subject.cc(status)).to eq [account_followers_url(status.account)]
+    end
+
+    it 'returns public collection for unlisted status' do
+      status = Fabricate(:status, visibility: :unlisted)
+      expect(subject.cc(status)).to eq ['https://www.w3.org/ns/activitystreams#Public']
+    end
+
+    it 'returns empty array for private status' do
+      status = Fabricate(:status, visibility: :private)
+      expect(subject.cc(status)).to eq []
+    end
+
+    it 'returns empty array for direct status' do
+      status = Fabricate(:status, visibility: :direct)
+      expect(subject.cc(status)).to eq []
+    end
+
+    it 'returns URIs of mentions for non-direct status' do
+      status    = Fabricate(:status, visibility: :public)
+      mentioned = Fabricate(:account)
+      status.mentions.create(account: mentioned)
+      expect(subject.cc(status)).to include(subject.uri_for(mentioned))
+    end
+  end
+
+  describe '#local_uri?' do
+    it 'returns false for non-local URI' do
+      expect(subject.local_uri?('http://example.com/123')).to be false
+    end
+
+    it 'returns true for local URIs' do
+      account = Fabricate(:account)
+      expect(subject.local_uri?(subject.uri_for(account))).to be true
+    end
+  end
+
+  describe '#uri_to_local_id' do
+    it 'returns the local ID' do
+      account = Fabricate(:account)
+      expect(subject.uri_to_local_id(subject.uri_for(account), :username)).to eq account.username
+    end
+  end
+
+  describe '#uri_to_resource' do
+    it 'returns the local resource' do
+      account = Fabricate(:account)
+      expect(subject.uri_to_resource(subject.uri_for(account), Account)).to eq account
+    end
+  end
+end