Bring abstract_controller up to date with rails/master

Resolved all the conflicts since 2.3.0 -> HEAD. Following is a list
of commits that could not be applied cleanly or are obviated with the
abstract_controller refactor. They all need to be revisited to ensure
that fixes made in 2.3 do not reappear in 3.0:

2259ecf368e6a6715966f69216e3ee86bf1a82a7
AR not available
  * This will be reimplemented with ActionORM or equivalent

06182ea02e92afad579998aa80144588e8865ac3
implicitly rendering a js response should not use the default layout
[#1844 state:resolved]
  * This will be handled generically

893e9eb99504705419ad6edac14d00e71cef5f12
Improve view rendering performance in development mode and reinstate
template recompiling in production [#1909 state:resolved]
  * We will need to reimplement rails-dev-boost on top of the refactor;
    the changes here are very implementation specific and cannot be
    cleanly applied. The following commits are implicated:

      199e750d46c04970b5e7684998d09405648ecbd4
      3942cb406e1d5db0ac00e03153809cc8dc4cc4db
      f8ea9f85d4f1e3e6f3b5d895bef6b013aa4b0690
      e3b166aab37ddc2fbab030b146eb61713b91bf55
      ae9f258e03c9fd5088da12c1c6cd216cc89a01f7
      44423126c6f6133a1d9cf1d0832b527e8711d40f

0cb020b4d6d838025859bd60fb8151c8e21b8e84
workaround for picking layouts based on wrong view_paths
[#1974 state:resolved]
  * The specifics of this commit no longer apply. Since it is a two-line
    commit, we will reimplement this change.

8c5cc66a831aadb159f3daaffa4208064c30af0e
make action_controller/layouts pick templates from the current instance's
view_paths instead of the class view_paths [#1974 state:resolved]
  * This does not apply at all. It should be trivial to apply the feature
    to the reimplemented ActionController::Base.

87e8b162463f13bd50d27398f020769460a770e3
fix HTML fallback for explicit templates [#2052 state:resolved]
  * There were a number of patches related to this that simply compounded
    each other. Basically none of them apply cleanly, and the underlying
    issue needs to be revisited. After discussing the underlying problem
    with Koz, we will defer these fixes for further discussion.

4 files changed, 18 insertions, 87 deletions

diff --git a/activesupport/lib/active_support/testing/assertions.rb b/activesupport/lib/active_support/testing/assertions.rb
index ce2f44efd6..ca51adba1e 100644
--- a/activesupport/lib/active_support/testing/assertions.rb
+++ b/activesupport/lib/active_support/testing/assertions.rb
@@ -31,13 +31,17 @@ module ActiveSupport
       #   assert_difference 'Article.count', -1, "An Article should be destroyed" do
       #     post :delete, :id => ...
       #   end
-      def assert_difference(expressions, difference = 1, message = nil, &block)
-        expression_evaluations = Array(expressions).collect{ |expression| lambda { eval(expression, block.send(:binding)) } }
+      def assert_difference(expression, difference = 1, message = nil, &block)
+        b = block.send(:binding)
+        exps = Array.wrap(expression)
+        before = exps.map { |e| eval(e, b) }
 
-        original_values = expression_evaluations.inject([]) { |memo, expression| memo << expression.call }
         yield
-        expression_evaluations.each_with_index do |expression, i|
-          assert_equal original_values[i] + difference, expression.call, message
+
+        exps.each_with_index do |e, i|
+          error = "#{e.inspect} didn't change by #{difference}"
+          error = "#{message}.\n#{error}" if message
+          assert_equal(before[i] + difference, eval(e, b), error)
         end
       end
 
@@ -53,8 +57,8 @@ module ActiveSupport
       #   assert_no_difference 'Article.count', "An Article should not be destroyed" do
       #     post :create, :article => invalid_attributes
       #   end
-      def assert_no_difference(expressions, message = nil, &block)
-        assert_difference expressions, 0, message, &block
+      def assert_no_difference(expression, message = nil, &block)
+        assert_difference expression, 0, message, &block
       end
     end
   end
diff --git a/activesupport/lib/active_support/testing/core_ext/test.rb b/activesupport/lib/active_support/testing/core_ext/test.rb
deleted file mode 100644
index d3f38f0bc7..0000000000
--- a/activesupport/lib/active_support/testing/core_ext/test.rb
+++ /dev/null
@@ -1,6 +0,0 @@
-require 'active_support/testing/core_ext/test/unit/assertions'
-require 'active_support/testing/setup_and_teardown'
-
-class Test::Unit::TestCase #:nodoc:
-  include ActiveSupport::Testing::SetupAndTeardown
-end
\ No newline at end of file
diff --git a/activesupport/lib/active_support/testing/core_ext/test/unit/assertions.rb b/activesupport/lib/active_support/testing/core_ext/test/unit/assertions.rb
deleted file mode 100644
index e5853bf828..0000000000
--- a/activesupport/lib/active_support/testing/core_ext/test/unit/assertions.rb
+++ /dev/null
@@ -1,72 +0,0 @@
-require 'test/unit/assertions'
-module Test
-  module Unit
-    #--
-    # FIXME: no Proc#binding in Ruby 2, must change this API
-    #++
-    module Assertions
-      # Test numeric difference between the return value of an expression as a result of what is evaluated
-      # in the yielded block.
-      #
-      #   assert_difference 'Article.count' do
-      #     post :create, :article => {...}
-      #   end
-      #
-      # An arbitrary expression is passed in and evaluated.
-      #
-      #   assert_difference 'assigns(:article).comments(:reload).size' do
-      #     post :create, :comment => {...}
-      #   end
-      #
-      # An arbitrary positive or negative difference can be specified. The default is +1.
-      #
-      #   assert_difference 'Article.count', -1 do
-      #     post :delete, :id => ...
-      #   end
-      #
-      # An array of expressions can also be passed in and evaluated.
-      #
-      #   assert_difference [ 'Article.count', 'Post.count' ], +2 do
-      #     post :create, :article => {...}
-      #   end
-      #
-      # A error message can be specified.
-      #
-      #   assert_difference 'Article.count', -1, "An Article should be destroyed" do
-      #     post :delete, :id => ...
-      #   end
-      def assert_difference(expressions, difference = 1, message = nil, &block)
-        expression_evaluations = Array(expressions).map do |expression|
-          [expression, lambda do
-            eval(expression, block.__send__(:binding))
-          end]
-        end
-
-        original_values = expression_evaluations.inject([]) { |memo, expression| memo << expression[1].call }
-        yield
-        expression_evaluations.each_with_index do |expression, i|
-          full_message = ""
-          full_message << "#{message}.\n" if message
-          full_message << "<#{expression[0]}> was the expression that failed"
-          assert_equal original_values[i] + difference, expression[1].call, full_message
-        end
-      end
-
-      # Assertion that the numeric result of evaluating an expression is not changed before and after
-      # invoking the passed in block.
-      #
-      #   assert_no_difference 'Article.count' do
-      #     post :create, :article => invalid_attributes
-      #   end
-      #
-      # A error message can be specified.
-      #
-      #   assert_no_difference 'Article.count', "An Article should not be destroyed" do
-      #     post :create, :article => invalid_attributes
-      #   end
-      def assert_no_difference(expressions, message = nil, &block)
-        assert_difference expressions, 0, message, &block
-      end
-    end
-  end
-end
diff --git a/activesupport/lib/active_support/testing/setup_and_teardown.rb b/activesupport/lib/active_support/testing/setup_and_teardown.rb
index 6248bf1921..4537c30e9c 100644
--- a/activesupport/lib/active_support/testing/setup_and_teardown.rb
+++ b/activesupport/lib/active_support/testing/setup_and_teardown.rb
@@ -8,7 +8,7 @@ module ActiveSupport
           include ActiveSupport::Callbacks
           define_callbacks :setup, :teardown
 
-          if defined? MiniTest
+          if defined?(MiniTest::Assertions) && TestCase < MiniTest::Assertions
             include ForMiniTest
           elsif defined? Spec
             include ForRspec
@@ -47,7 +47,12 @@ module ActiveSupport
           return if @method_name.to_s == "default_test"
 
           if using_mocha = respond_to?(:mocha_verify)
-            assertion_counter = Mocha::TestCaseAdapter::AssertionCounter.new(result)
+            assertion_counter_klass = if defined?(Mocha::TestCaseAdapter::AssertionCounter)
+                                        Mocha::TestCaseAdapter::AssertionCounter
+                                      else
+                                        Mocha::Integration::TestUnit::AssertionCounter
+                                      end
+            assertion_counter = assertion_counter_klass.new(result)
           end
 
           yield(Test::Unit::TestCase::STARTED, name)