pass variants in rather than mutating the request.

Variants are typically set in the controller based on some attribute of
the request that the browser sent.  We should make our tests more in
line with reality by doing the same and not mutating the request object.

actionpack/test/controller/mime/respond_to_test.rb

@@ -4,6 +4,13 @@
 class RespondToController < ActionController::Base
   layout :set_layout
 
+  before_action {
+    case params[:v]
+    when String then request.variant = params[:v].to_sym
+    when Array then request.variant = params[:v].map(&:to_sym)
+    end
+  }
+
   def html_xml_or_rss
     respond_to do |type|
       type.html { render :text => "HTML"    }
@@ -612,8 +619,7 @@ def test_invalid_variant
     logger = ActiveSupport::LogSubscriber::TestHelper::MockLogger.new
     old_logger, ActionController::Base.logger = ActionController::Base.logger, logger
 
-    @request.variant = :invalid
-    get :variant_with_implicit_rendering
+    get :variant_with_implicit_rendering, params: { v: :invalid }
     assert_response :no_content
     assert_equal 1, logger.logged(:info).select{ |s| s =~ /No template found/ }.size, "Implicit head :no_content not logged"
   ensure
@@ -626,28 +632,24 @@ def test_variant_not_set_regular_template_missing
   end
 
   def test_variant_with_implicit_rendering
-    @request.variant = :implicit
-    get :variant_with_implicit_rendering
+    get :variant_with_implicit_rendering, params: { v: :implicit }
     assert_response :no_content
   end
 
   def test_variant_with_implicit_template_rendering
-    @request.variant = :mobile
-    get :variant_with_implicit_rendering
+    get :variant_with_implicit_rendering, params: { v: :mobile }
     assert_equal "text/html", @response.content_type
     assert_equal "mobile", @response.body
   end
 
   def test_variant_with_format_and_custom_render
-    @request.variant = :phone
-    get :variant_with_format_and_custom_render
+    get :variant_with_format_and_custom_render, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "mobile", @response.body
   end
 
   def test_multiple_variants_for_format
-    @request.variant = :tablet
-    get :multiple_variants_for_format
+    get :multiple_variants_for_format, params: { v: :tablet }
     assert_equal "text/html", @response.content_type
     assert_equal "tablet", @response.body
   end
@@ -667,32 +669,27 @@ def test_variant_inline_syntax
     assert_equal "text/html", @response.content_type
     assert_equal "none", @response.body
 
-    @request.variant = :phone
-    get :variant_inline_syntax
+    get :variant_inline_syntax, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
   end
 
   def test_variant_inline_syntax_without_block
-    @request.variant = :phone
-    get :variant_inline_syntax_without_block
+    get :variant_inline_syntax_without_block, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
   end
 
   def test_variant_any
-    @request.variant = :phone
-    get :variant_any
+    get :variant_any, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
 
-    @request.variant = :tablet
-    get :variant_any
+    get :variant_any, params: { v: :tablet }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
 
-    @request.variant = :phablet
-    get :variant_any
+    get :variant_any, params: { v: :phablet }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
   end
@@ -702,54 +699,45 @@ def test_variant_any_any
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
 
-    @request.variant = :phone
-    get :variant_any_any
+    get :variant_any_any, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
 
-    @request.variant = :yolo
-    get :variant_any_any
+    get :variant_any_any, params: { v: :yolo }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
   end
 
   def test_variant_inline_any
-    @request.variant = :phone
-    get :variant_any
+    get :variant_any, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
 
-    @request.variant = :tablet
-    get :variant_inline_any
+    get :variant_inline_any, params: { v: :tablet }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
 
-    @request.variant = :phablet
-    get :variant_inline_any
+    get :variant_inline_any, params: { v: :phablet }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
   end
 
   def test_variant_inline_any_any
-    @request.variant = :phone
-    get :variant_inline_any_any
+    get :variant_inline_any_any, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
 
-    @request.variant = :yolo
-    get :variant_inline_any_any
+    get :variant_inline_any_any, params: { v: :yolo }
     assert_equal "text/html", @response.content_type
     assert_equal "any", @response.body
   end
 
   def test_variant_any_implicit_render
-    @request.variant = :tablet
-    get :variant_any_implicit_render
+    get :variant_any_implicit_render, params: { v: :tablet }
     assert_equal "text/html", @response.content_type
     assert_equal "tablet", @response.body
 
-    @request.variant = :phablet
-    get :variant_any_implicit_render
+    get :variant_any_implicit_render, params: { v: :phablet }
     assert_equal "text/html", @response.content_type
     assert_equal "phablet", @response.body
   end
@@ -759,36 +747,31 @@ def test_variant_any_with_none
     assert_equal "text/html", @response.content_type
     assert_equal "none or phone", @response.body
 
-    @request.variant = :phone
-    get :variant_any_with_none
+    get :variant_any_with_none, params: { v: :phone }
     assert_equal "text/html", @response.content_type
     assert_equal "none or phone", @response.body
   end
 
   def test_format_any_variant_any
-    @request.variant = :tablet
-    get :format_any_variant_any, format: :js
+    get :format_any_variant_any, format: :js, params: { v: :tablet }
     assert_equal "text/javascript", @response.content_type
     assert_equal "tablet", @response.body
   end
 
   def test_variant_negotiation_inline_syntax
-    @request.variant = [:tablet, :phone]
-    get :variant_inline_syntax_without_block
+    get :variant_inline_syntax_without_block, params: { v: [:tablet, :phone] }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
   end
 
   def test_variant_negotiation_block_syntax
-    @request.variant = [:tablet, :phone]
-    get :variant_plus_none_for_format
+    get :variant_plus_none_for_format, params: { v: [:tablet, :phone] }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
   end
 
   def test_variant_negotiation_without_block
-    @request.variant = [:tablet, :phone]
-    get :variant_inline_syntax_without_block
+    get :variant_inline_syntax_without_block, params: { v: [:tablet, :phone] }
     assert_equal "text/html", @response.content_type
     assert_equal "phone", @response.body
   end