Queue the events in the event bus before the bus is started.

lib/cucumber/core.rb

@@ -8,7 +8,7 @@
 module Cucumber
   module Core
 
-    def execute(gherkin_documents, filters = [], event_bus = EventBus.new)
+    def execute(gherkin_documents, filters = [], event_bus = create_and_start_event_bus)
       yield event_bus if block_given?
       receiver = Test::Runner.new(event_bus)
       compile gherkin_documents, receiver, filters
@@ -39,5 +39,10 @@ def compose(filters, last_receiver)
       end
     end
 
+    def create_and_start_event_bus
+      event_bus = EventBus.new
+      event_bus.start
+      event_bus
+    end
   end
 end

lib/cucumber/core/event_bus.rb

@@ -9,12 +9,22 @@ module Core
     # to subscribe to events that fire as your tests are executed.
     #
     class EventBus
-      attr_reader :event_types
+      attr_reader :event_types, :started
+      private :started
 
       # @param [Hash{Symbol => Class}] a hash of event types to use on the bus
       def initialize(registry = Events.registry)
         @event_types = registry.freeze
         @handlers = {}
+        @started = false
+      end
+
+      def start
+        event_queue.each do |event|
+          do_broadcast(event)
+        end
+        reset_event_queue
+        @started = true
       end
 
       # Register for an event. The handler proc will be called back with each of the attributes
@@ -29,7 +39,11 @@ def on(event_id, handler_object = nil, &handler_proc)
       # Broadcast an event
       def broadcast(event)
         raise ArgumentError, "Event type #{event.class} is not registered. Try one of these:\n#{event_types.values.join("\n")}" unless is_registered_type?(event.class)
-        handlers_for(event.class).each { |handler| handler.call(event) }
+        if started
+          do_broadcast(event)
+        else
+          event_queue << event
+        end
       end
 
       def method_missing(event_id, *args)
@@ -45,6 +59,10 @@ def handlers_for(event_class)
         @handlers[event_class.to_s] ||= []
       end
 
+      def do_broadcast(event)
+        handlers_for(event.class).each { |handler| handler.call(event) }
+      end
+
       def is_registered_id?(event_id)
         event_types.keys.include?(event_id)
       end
@@ -58,6 +76,14 @@ def validate_handler_and_event_id!(handler, event_id)
         raise ArgumentError, "Please use a symbol for the event_id" unless event_id.is_a?(Symbol)
         raise ArgumentError, "Event ID #{event_id} is not recognised. Try one of these:\n#{event_types.keys.join("\n")}" unless is_registered_id?(event_id)
       end
+
+      def event_queue
+        @event_queue ||= []
+      end
+
+      def reset_event_queue
+        @event_queue = []
+      end
     end
 
   end

spec/cucumber/core/event_bus_spec.rb

@@ -18,6 +18,8 @@ class TestEvent < Core::Event.new(:some_attribute)
 
       context "broadcasting events" do
 
+        before(:each) { event_bus.start }
+
         it "can broadcast by calling a method named after the event ID" do
           called = false
           event_bus.on(:test_event) {called = true }
@@ -82,7 +84,23 @@ class TestEvent < Core::Event.new(:some_attribute)
 
       end
 
+      context "queuing events" do
+
+        it "before the event bus is started, events are queued and broadcasted when started" do
+          called = false
+          event_bus.on(:test_event) {called = true }
+          event_bus.test_event
+          expect(called).to be false
+          event_bus.start
+          expect(called).to be true
+        end
+
+      end
+
       context "subscribing to events" do
+
+        before(:each) { event_bus.start }
+
         it "allows subscription by symbol (Event ID)" do
           received_payload = nil
           event_bus.on(:test_event) do |event|
@@ -138,14 +156,19 @@ def on_test_event(event)
 
       end
 
-      it "will let you inspect the registry" do
-        expect(event_bus.event_types[:test_event]).to eq Events::TestEvent
-      end
+      context "event registry" do
 
-      it "won't let you modify the registry" do
-        expect { event_bus.event_types[:foo] = :bar }.to raise_error(RuntimeError)
-      end
+        before(:each) { event_bus.start }
 
+        it "will let you inspect the registry" do
+          expect(event_bus.event_types[:test_event]).to eq Events::TestEvent
+        end
+
+        it "won't let you modify the registry" do
+          expect { event_bus.event_types[:foo] = :bar }.to raise_error(RuntimeError)
+        end
+
+      end
     end
   end
 end

spec/cucumber/core/report/summary_spec.rb

@@ -16,7 +16,10 @@ module Cucumber::Core::Report
     let(:duration) { double }
     let(:exception) { double }
 
-    before(:each) { @summary = Summary.new(event_bus) }
+    before(:each) do
+      @summary = Summary.new(event_bus)
+      event_bus.start
+    end
 
     context "test case summary" do
       let(:test_case) { double }

spec/cucumber/core_spec.rb

@@ -201,6 +201,9 @@ def expect_tag_excess(error_message)
     end
 
     describe "executing a test suite" do
+      let(:event_bus) { Core::EventBus.new }
+
+      before(:each) { event_bus.start }
 
       it "fires events" do
         gherkin = gherkin do
@@ -273,7 +276,6 @@ def expect_tag_excess(error_message)
             end
           end
 
-          event_bus = Core::EventBus.new
           report = Core::Report::Summary.new(event_bus)
           execute [gherkin], [Core::Test::Filters::ActivateStepsForSelfTest.new], event_bus
 
@@ -317,7 +319,6 @@ def test_case(test_case)
           end
           logger = []
 
-          event_bus = Core::EventBus.new
           report = Core::Report::Summary.new(event_bus)
           execute [gherkin], [WithAroundHooks.new(logger)], event_bus
 
@@ -352,7 +353,6 @@ def test_case(test_case)
           end
         end
 
-        event_bus = Core::EventBus.new
         report = Core::Report::Summary.new(event_bus)
         execute [gherkin], [ Cucumber::Core::Test::TagFilter.new(['@a']) ], event_bus
 
@@ -371,7 +371,6 @@ def test_case(test_case)
           end
         end
 
-        event_bus = Core::EventBus.new
         report = Core::Report::Summary.new(event_bus)
         execute [gherkin], [ Cucumber::Core::Test::NameFilter.new([/scenario/]) ], event_bus