handle empty responses when polling

that can be result of some interrupted connection

like https://travis-ci.org/lowjoel/message_bus-client/jobs/266253959

lib/message_bus_client/connection.rb

@@ -27,10 +27,10 @@ def initialize(base_url)
 
   def diagnostics; end
 
-  def start
+  def start(**options)
     return unless @state == INITIALISED || stopped?
 
-    @connection = Excon.new(server_endpoint, persistent: true)
+    @connection = Excon.new(server_endpoint, persistent: true, **options)
 
     @runner = Thread.new(&method(:runner))
     @runner.name = "MessageBusClient (#{@client_id})"

lib/message_bus_client/message_handler.rb

@@ -51,7 +51,7 @@ def handle_chunk(chunk, _remaining_bytes, _total_bytes)
   end
 
   def handle_response(body)
-    handle_messages(JSON.parse(body))
+    handle_messages(JSON.parse(body)) unless body.empty?
   end
 
   def try_consume_message

spec/message_bus_client_spec.rb

@@ -113,6 +113,16 @@ def write_message(message, user = 'message_bus_client')
         sleep(1)
       end
     end
+
+    it 'handles empty message' do
+      expect(subject).to receive(:handle_response).with('').and_call_original.at_least(:once)
+
+      Excon.stub({}, body: '', status: 200)
+
+      subject.start(mock: true, persistent: false)
+
+      sleep(0.1)
+    end
   end
 
   it 'allows pausing messages' do

spec/spec_helper.rb

@@ -94,4 +94,17 @@
   # test failures related to randomization by passing the same `--seed` value
   # as the one that triggered the failure.
   Kernel.srand config.seed
+
+  config.after(:each) do
+    Thread.list.each do |thread|
+      if thread.name&.match('MessageBusClient')
+        thread.kill
+        thread.join
+      end
+    end
+  end
+
+  config.after(:each) do
+    Excon.stubs.clear
+  end
 end