Move test support files out of lib

Those files are only used for testing spring, so we should not expose in
the gem

Author: rafaelfranca

lib/spring/test.rb

@@ -1,5 +1,5 @@
 require "bundler/setup"
 require "minitest/autorun"
 
-require "spring/test"
+require_relative "support/test"
 Spring::Test.root = File.expand_path('..', __FILE__)

test/helper.rb

@@ -0,0 +1,18 @@
+require "active_support"
+require "active_support/test_case"
+
+ActiveSupport.test_order = :random
+
+module Spring
+  module Test
+    class << self
+      attr_accessor :root
+    end
+
+    require_relative "application"
+    require_relative "application_generator"
+    require_relative "rails_version"
+    require_relative "watcher_test"
+    require_relative "acceptance_test"
+  end
+end

lib/spring/test/acceptance_test.rb renamed to test/support/acceptance_test.rb

@@ -1,5 +1,5 @@
 require_relative "../helper"
-require "spring/test/watcher_test"
+require_relative "../support/watcher_test"
 require "spring/watcher/polling"
 
 class PollingWatcherTest < Spring::Test::WatcherTest