tests, define `Rails.root` before loading Action Mailer.

Since `bin/test` would define `Rails.root` before loading AM but `bundle
exec rake` would define it after loading AM, this lead to the following
test failure when using `bin/test`:

```
--- expected
+++ actual
@@ -1 +1 @@
-{:location=>"/var/folders/_r/9kh50y4j0vn7zgg2p65z1lcm0000gn/T/mails"}
+{:location=>"/Users/senny/Projects/rails/actionmailer/tmp/mails"}
```

This patch ensures that `Rails.root` is defined when loading AM to
achieve consistent test results.

1 files changed, 6 insertions, 6 deletions

diff --git a/actionmailer/test/abstract_unit.rb b/actionmailer/test/abstract_unit.rb
index 85d3629514..285b2cfcb5 100644
--- a/actionmailer/test/abstract_unit.rb
+++ b/actionmailer/test/abstract_unit.rb
@@ -8,6 +8,12 @@ silence_warnings do
   Encoding.default_external = "UTF-8"
 end
 
+module Rails
+  def self.root
+    File.expand_path('../', File.dirname(__FILE__))
+  end
+end
+
 require 'active_support/testing/autorun'
 require 'active_support/testing/method_call_assertions'
 require 'action_mailer'
@@ -26,12 +32,6 @@ I18n.enforce_available_locales = false
 FIXTURE_LOAD_PATH = File.expand_path('fixtures', File.dirname(__FILE__))
 ActionMailer::Base.view_paths = FIXTURE_LOAD_PATH
 
-module Rails
-  def self.root
-    File.expand_path('../', File.dirname(__FILE__))
-  end
-end
-
 # Skips the current run on Rubinius using Minitest::Assertions#skip
 def rubinius_skip(message = '')
   skip message if RUBY_ENGINE == 'rbx'