Add end-to-end (system) tests (#25461)

spec/spec_helper.rb

@@ -52,3 +52,80 @@ def expect_push_bulk_to_match(klass, matcher)
     'args' => matcher,
   }))
 end
+
+class StreamingServerManager
+  @running_thread = nil
+
+  def initialize
+    at_exit { stop }
+  end
+
+  def start(port: 4020)
+    return if @running_thread
+
+    queue = Queue.new
+
+    @queue = queue
+
+    @running_thread = Thread.new do
+      Open3.popen2e(
+        {
+          'REDIS_NAMESPACE' => ENV.fetch('REDIS_NAMESPACE'),
+          'DB_NAME' => "#{ENV.fetch('DB_NAME', 'mastodon')}_test#{ENV.fetch('TEST_ENV_NUMBER', '')}",
+          'RAILS_ENV' => ENV.fetch('RAILS_ENV', 'test'),
+          'NODE_ENV' => ENV.fetch('STREAMING_NODE_ENV', 'development'),
+          'PORT' => port.to_s,
+        },
+        'node index.js', # must not call yarn here, otherwise it will fail because yarn does not send signals to its child process
+        chdir: Rails.root.join('streaming')
+      ) do |_stdin, stdout_err, process_thread|
+        status = :starting
+
+        # Spawn a thread to listen on streaming server output
+        output_thread = Thread.new do
+          stdout_err.each_line do |line|
+            Rails.logger.info "Streaming server: #{line}"
+
+            if status == :starting && line.match('Streaming API now listening on')
+              status = :started
+              @queue.enq 'started'
+            end
+          end
+        end
+
+        # And another thread to listen on commands from the main thread
+        loop do
+          msg = queue.pop
+
+          case msg
+          when 'stop'
+            # we need to properly stop the reading thread
+            output_thread.kill
+
+            # Then stop the node process
+            Process.kill('KILL', process_thread.pid)
+
+            # And we stop ourselves
+            @running_thread.kill
+          end
+        end
+      end
+    end
+
+    # wait for 10 seconds for the streaming server to start
+    Timeout.timeout(10) do
+      loop do
+        break if @queue.pop == 'started'
+      end
+    end
+  end
+
+  def stop
+    return unless @running_thread
+
+    @queue.enq 'stop'
+
+    # Wait for the thread to end
+    @running_thread.join
+  end
+end