Simplify code by taking advantage of latest mocha (v0.13.0).

This only works with mocha v0.13.0 or later.

Note that this also fixes a few subtle bugs present in the current
implementation :-

* Mocha was raising a `MiniTest::Assertion` instead of a
  `Mocha::ExpectationError` as intended. The latter is not recognized by
  MiniTest as an assertion failure and so it is recorded as a test
  *error*, not a test *failure* as it ought to. This leads to
  potentially confusing output in the test results.

* Mocha verification should happen as part of the test. The verification
  of expectations is equivalent to a set of assertions. These assertions
  should happen as *part of* the test so that they have a chance to
  cause the test to fail, and not just as part of the teardown. Also if
  an assertion fails during the test, then there is no need to verify
  expectations, because only the first assertion failure is normally
  reported and all subsequent bets are off.

* Expectation verification should be counted as an assertion. Mocha
  cannot record each expectation verification as an assertion, because
  we weren't passing in an assertion counter to `#mocha_verify`.

2 files changed, 5 insertions, 25 deletions

diff --git a/activesupport/lib/active_support/test_case.rb b/activesupport/lib/active_support/test_case.rb
index 8b06739b7f..c96ad17aba 100644
--- a/activesupport/lib/active_support/test_case.rb
+++ b/activesupport/lib/active_support/test_case.rb
@@ -5,16 +5,18 @@ require 'active_support/testing/setup_and_teardown'
 require 'active_support/testing/assertions'
 require 'active_support/testing/deprecation'
 require 'active_support/testing/isolation'
-require 'active_support/testing/mocha_module'
 require 'active_support/testing/constant_lookup'
 require 'active_support/core_ext/kernel/reporting'
 require 'active_support/deprecation'
 
+begin
+  silence_warnings { require 'mocha/setup' }
+rescue LoadError
+end
+
 module ActiveSupport
   class TestCase < ::MiniTest::Spec
 
-    include ActiveSupport::Testing::MochaModule
-
     # Use AS::TestCase for the base class when describing a model
     register_spec_type(self) do |desc|
       Class === desc && desc < ActiveRecord::Base
diff --git a/activesupport/lib/active_support/testing/mocha_module.rb b/activesupport/lib/active_support/testing/mocha_module.rb
deleted file mode 100644
index 833dc867f0..0000000000
--- a/activesupport/lib/active_support/testing/mocha_module.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-module ActiveSupport
-  module Testing
-    module MochaModule
-      begin
-        require 'mocha/api'
-        include Mocha::API
-
-        def before_setup
-          mocha_setup
-          super
-        end
-
-        def after_teardown
-          super
-          mocha_verify
-          mocha_teardown
-        end
-      rescue LoadError
-      end
-    end
-  end
-end