Migrating xhr methods to keyword arguments syntax

in `ActionController::TestCase` and
`ActionDispatch::Integration`

Old syntax:

    `xhr :get, :create, params: { id: 1 }`

New syntax example:

    `get :create, params: { id: 1 }, xhr: true`

2 files changed, 34 insertions, 11 deletions

diff --git a/actionpack/lib/action_controller/test_case.rb b/actionpack/lib/action_controller/test_case.rb
index 15e587bcea..a15a4bfab1 100644
--- a/actionpack/lib/action_controller/test_case.rb
+++ b/actionpack/lib/action_controller/test_case.rb
@@ -546,8 +546,13 @@ module ActionController
       end
 
       def xml_http_request(*args)
+        ActiveSupport::Deprecation.warn(<<-MSG.strip_heredoc)
+          xhr and xml_http_request methods are deprecated in favor of
+          `get :index, xhr: true` and `post :create, xhr: true`
+        MSG
+
         @request.env['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
-        @request.env['HTTP_ACCEPT'] ||=  [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
+        @request.env['HTTP_ACCEPT'] ||= [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
         __send__(*args).tap do
           @request.env.delete 'HTTP_X_REQUESTED_WITH'
           @request.env.delete 'HTTP_ACCEPT'
@@ -599,7 +604,7 @@ module ActionController
         check_required_ivars
 
         if kwarg_request?(*args)
-          parameters, session, body, flash, http_method, format = args[0].values_at(:params, :session, :body, :flash, :method, :format)
+          parameters, session, body, flash, http_method, format, xhr = args[0].values_at(:params, :session, :body, :flash, :method, :format, :xhr)
         else
           http_method, parameters, session, flash = args
           format = nil
@@ -655,6 +660,11 @@ module ActionController
         @request.session.update(session) if session
         @request.flash.update(flash || {})
 
+        if xhr
+          @request.env['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
+          @request.env['HTTP_ACCEPT'] ||= [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
+        end
+
         @controller.request  = @request
         @controller.response = @response
 
@@ -678,6 +688,11 @@ module ActionController
           @request.session['flash'] = flash_value
         end
 
+        if xhr
+          @request.env.delete 'HTTP_X_REQUESTED_WITH'
+          @request.env.delete 'HTTP_ACCEPT'
+        end
+
         @response
       end
 
@@ -738,7 +753,7 @@ module ActionController
         end
       end
 
-      REQUEST_KWARGS = %i(params session flash method body)
+      REQUEST_KWARGS = %i(params session flash method body xhr)
       def kwarg_request?(*args)
         args[0].respond_to?(:keys) && (
           (args[0].key?(:format) && args[0].keys.size == 1) ||
diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index db6233840a..876a980ff1 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -92,11 +92,12 @@ module ActionDispatch
           end
         end
 
-        headers ||= {}
-        headers.merge!(env) if env
-        headers['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
-        headers['HTTP_ACCEPT'] ||= [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
-        process(request_method, path, params: params, headers: headers)
+        ActiveSupport::Deprecation.warn(<<-MSG.strip_heredoc)
+          xhr and xml_http_request methods are deprecated in favor of
+          `get "/posts", xhr: true` and `post "/posts/1", xhr: true`
+        MSG
+
+        process(request_method, path, params: params, headers: headers, xhr: true)
       end
       alias xhr :xml_http_request
 
@@ -306,7 +307,7 @@ module ActionDispatch
           end
         end
 
-        REQUEST_KWARGS = %i(params headers env)
+        REQUEST_KWARGS = %i(params headers env xhr)
         def kwarg_request?(*args)
           args[0].respond_to?(:keys) && args[0].keys.any? { |k| REQUEST_KWARGS.include?(k) }
         end
@@ -329,7 +330,7 @@ module ActionDispatch
         end
 
         # Performs the actual request.
-        def process(method, path, params: nil, headers: nil, env: nil)
+        def process(method, path, params: nil, headers: nil, env: nil, xhr: false)
           if path =~ %r{://}
             location = URI.parse(path)
             https! URI::HTTPS === location if location.scheme
@@ -354,6 +355,13 @@ module ActionDispatch
             "CONTENT_TYPE"   => "application/x-www-form-urlencoded",
             "HTTP_ACCEPT"    => accept
           }
+
+          if xhr
+            headers ||= {}
+            headers['HTTP_X_REQUESTED_WITH'] = 'XMLHttpRequest'
+            headers['HTTP_ACCEPT'] ||= [Mime::JS, Mime::HTML, Mime::XML, 'text/xml', Mime::ALL].join(', ')
+          end
+
           # this modifies the passed request_env directly
           if headers.present?
             Http::Headers.new(request_env).merge!(headers)
@@ -377,7 +385,7 @@ module ActionDispatch
 
           @controller = session.last_request.env['action_controller.instance']
 
-          return response.status
+          response.status
         end
 
         def build_full_uri(path, env)