Update specs that check mime type of header from content_type to medi…

…a_type (#401)

See: How ActionDispatch::Response#content_type Changed Between Rails 5.2 to 6.1 - FastRuby.io | Rails Upgrade Service

spec/controllers/application_controller_spec.rb

@@ -9,7 +9,7 @@
       before(:each){ get :root, format: :json }
 
       it 'should render json' do
-        expect(response.content_type).to eql 'application/json'
+        expect(response.media_type).to eql 'application/json'
       end
 
       it 'should list resources' do
@@ -21,7 +21,7 @@
       before(:each){ get :root, format: :json_api }
 
       it 'should render json' do
-        expect(response.content_type).to eql 'application/json'
+        expect(response.media_type).to eql 'application/json'
       end
 
       it 'should list resources' do
@@ -36,7 +36,7 @@
       end
 
       it 'should render html' do
-        expect(response.content_type).to eql 'text/html'
+        expect(response.media_type).to eql 'text/html'
       end
 
       it 'should redirect' do

spec/controllers/comments_controller_spec.rb

@@ -140,7 +140,7 @@
         end
 
         it 'should be json' do
-          expect(response.content_type).to eql 'application/json'
+          expect(response.media_type).to eql 'application/json'
         end
 
         it 'should be an object' do

spec/support/shared_examples_for_controller_actions.rb

@@ -19,7 +19,7 @@
 
     it 'should be json' do
       # starting from Rails 5+, if responding with 204, content-type of response is set by Rails as nil
-      expect(response.content_type).to eql 'application/json' unless response.status == 204
+      expect(response.media_type).to eql 'application/json' unless response.status == 204
     end
 
     it 'should be an object' do

spec/support/shared_examples_for_controller_creating.rb

@@ -45,7 +45,7 @@
       end
 
       it 'should be json' do
-        expect(response.content_type).to eql 'application/json'
+        expect(response.media_type).to eql 'application/json'
       end
 
       it 'should be an object' do

spec/support/shared_examples_for_controller_updating.rb

@@ -48,7 +48,7 @@
       end
 
       it 'should be json' do
-        expect(response.content_type).to eql 'application/json'
+        expect(response.media_type).to eql 'application/json'
       end
 
       it 'should be an object' do