Add integration tests for mastodon-streaming (#36025)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>
Co-authored-by: David Roetzel <david@roetzel.de>

spec/system/streaming/channel_subscriptions_spec.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+require 'debug'
+
+RSpec.describe 'Channel Subscriptions', :inline_jobs, :streaming do
+  let(:application) { Fabricate(:application, confidential: false) }
+  let(:scopes) { nil }
+  let(:access_token) { Fabricate(:accessible_access_token, resource_owner_id: user_account.user.id, application: application, scopes: scopes) }
+
+  let(:user_account) { Fabricate(:account, username: 'alice', domain: nil) }
+  let(:bob_account) { Fabricate(:account, username: 'bob') }
+
+  after do
+    streaming_client.close
+  end
+
+  context 'when the access token has read scope' do
+    let(:scopes) { 'read' }
+
+    it 'can subscribing to the public:local channel' do
+      streaming_client.authenticate(access_token.token)
+
+      streaming_client.connect
+      streaming_client.subscribe('public:local')
+
+      # We need to publish a status as there is no positive acknowledgement of
+      # subscriptions:
+      status = PostStatusService.new.call(bob_account, text: 'Hello @alice')
+
+      # And then we want to receive that status:
+      message = streaming_client.wait_for_message
+
+      expect(message).to include(
+        stream: be_an(Array).and(contain_exactly('public:local')),
+        event: 'update',
+        payload: include(
+          id: status.id.to_s
+        )
+      )
+    end
+  end
+
+  context 'when the access token cannot read notifications' do
+    let(:scopes) { 'read:statuses' }
+
+    it 'cannot subscribing to the user:notifications channel' do
+      streaming_client.authenticate(access_token.token)
+
+      streaming_client.connect
+      streaming_client.subscribe('user:notification')
+
+      # We should receive an error back immediately:
+      message = streaming_client.wait_for_message
+
+      expect(message).to include(
+        error: 'Access token does not have the required scopes',
+        status: 401
+      )
+    end
+  end
+end