Adding tests, spy dependency

Gemfile

@@ -2,3 +2,7 @@ source 'https://rubygems.org'
 
 gemspec
 gem 'stackprof', platforms: :mri_21
+
+group :test do
+  gem 'spy', '0.4.1'
+end

History.md

@@ -3,6 +3,7 @@
 ## 3.0.0 / not yet released / branch "master"
 
 * ...
+* Optimize checking for block interrupts to reduce object allocation #380 [Jason Hiltz-Laforge, jasonhl] 
 * Properly set context rethrow_errors on render! #349 [Thierry Joyal, tjoyal]
 * Fix broken rendering of variables which are equal to false, see #345 [Florian Weingarten, fw42]
 * Remove ActionView template handler [Dylan Thacker-Smith, dylanahsmith]

lib/liquid/context.rb

@@ -73,7 +73,7 @@ module Liquid
 
     # are there any not handled interrupts?
     def has_interrupt?
-     !@interrupts.empty?
+      !@interrupts.empty?
     end
 
     # push an interrupt to the stack. this interrupt is considered not handled.

test/test_helper.rb

@@ -2,6 +2,7 @@
 
 require 'test/unit'
 require 'test/unit/assertions'
+require 'spy/integration'
 
 $:.unshift(File.join(File.expand_path(File.dirname(__FILE__)), '..', 'lib'))
 require 'liquid.rb'

test/unit/context_unit_test.rb

@@ -70,6 +70,10 @@ class ContextUnitTest < Test::Unit::TestCase
     @context = Liquid::Context.new
   end
 
+  def teardown
+    Spy.teardown
+  end
+
   def test_variables
     @context['string'] = 'string'
     assert_equal 'string', @context['string']
@@ -457,4 +461,16 @@ class ContextUnitTest < Test::Unit::TestCase
     assert_kind_of CategoryDrop, @context['category']
     assert_equal @context, @context['category'].context
   end
+
+  def test_use_empty_instead_of_any_in_interrupt_handling_to_avoid_lots_of_unnecessary_object_allocations
+    mock_any = Spy.on_instance_method(Array, :any?)
+    mock_empty = Spy.on_instance_method(Array, :empty?)
+    mock_has_interrupt = Spy.on(@context, :has_interrupt?).and_call_through
+
+    @context.has_interrupt?
+
+    refute mock_any.has_been_called?
+    assert mock_empty.has_been_called?
+  end 
+
 end # ContextTest