add code coverage to test suite

.gitignore

@@ -6,3 +6,4 @@ vmodl
 doc
 .yardoc
 *.rbc
+coverage

test/test_deserialization.rb

@@ -1,17 +1,9 @@
-begin
-  require 'cover_me'
-rescue LoadError
-  puts "Install the cover_me gem for code coverage"
-end
-
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class DeserializationTest < Test::Unit::TestCase
   def setup
     @soap = VIM.new(:ns => 'urn:vim25', :rev => '4.0')
-    @deserializer = RbVmomi::OldDeserializer.new @soap
+    @deserializer = RbVmomi::Deserializer.new @soap
   end
 
   def check str, expected, type

test/test_emit_request.rb

@@ -1,6 +1,4 @@
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class EmitRequestTest < Test::Unit::TestCase
   MO = VIM::VirtualMachine(nil, "foo")

test/test_exceptions.rb

@@ -1,6 +1,4 @@
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class ExceptionTest < Test::Unit::TestCase
   def test_fault

test/test_helper.rb

@@ -0,0 +1,14 @@
+coverage_tool = :simplecov if ENV['RBVMOMI_COVERAGE']
+
+case coverage_tool
+when :simplecov
+  require 'simplecov'
+  SimpleCov.start
+when :cover_me
+  require 'cover_me'
+end
+
+require 'rbvmomi'
+VIM = RbVmomi::VIM
+
+require 'test/unit'

test/test_misc.rb

@@ -1,6 +1,4 @@
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class MiscTest < Test::Unit::TestCase
   def test_overridden_const

test/test_parse_response.rb

@@ -1,6 +1,4 @@
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class ParseResponseTest < Test::Unit::TestCase
   def check desc, str, expected

test/test_serialization.rb

@@ -1,6 +1,4 @@
-require 'test/unit'
-require 'rbvmomi'
-VIM = RbVmomi::VIM unless Object.const_defined? :VIM
+require 'test_helper'
 
 class SerializationTest < Test::Unit::TestCase
   def check str, obj, type, array=false