Fix transient tests failures

Gemfile

@@ -15,3 +15,7 @@ if version == "master"
 else
   gem "rails", "~> #{version}.0"
 end
+
+group :test do
+  gem "timecop"
+end

test/action_controller/serialization_test.rb

@@ -203,9 +203,6 @@ def test_render_array_using_implicit_serializer_and_meta
       end
 
       def test_render_with_cache_enable
-        ActionController::Base.cache_store.clear
-        get :render_object_with_cache_enabled
-
         expected = {
           id: 1,
           title: 'New Post',
@@ -225,11 +222,16 @@ def test_render_with_cache_enable
           }
         }
 
-        assert_equal 'application/json', @response.content_type
-        assert_equal expected.to_json, @response.body
+        ActionController::Base.cache_store.clear
+        Timecop.freeze(DateTime.now) do
+          get :render_object_with_cache_enabled
 
-        get :render_changed_object_with_cache_enabled
-        assert_equal expected.to_json, @response.body
+          assert_equal 'application/json', @response.content_type
+          assert_equal expected.to_json, @response.body
+
+          get :render_changed_object_with_cache_enabled
+          assert_equal expected.to_json, @response.body
+        end
 
         ActionController::Base.cache_store.clear
         get :render_changed_object_with_cache_enabled
@@ -285,21 +287,24 @@ def test_render_with_fragment_except_cache_enable
 
       def test_render_fragment_changed_object_with_relationship
         ActionController::Base.cache_store.clear
-        get :render_fragment_changed_object_with_relationship
-        response = JSON.parse(@response.body)
 
-        expected_return = {
-          "id"=>1,
-          "time"=>DateTime.now.to_s,
-          "post" => {
+        Timecop.freeze(DateTime.now) do
+          get :render_fragment_changed_object_with_relationship
+          response = JSON.parse(@response.body)
+
+          expected_return = {
             "id"=>1,
-            "title"=>"New Post",
-            "body"=>"Body"
+            "time"=>DateTime.now.to_s,
+            "post" => {
+              "id"=>1,
+              "title"=>"New Post",
+              "body"=>"Body"
+            }
           }
-        }
 
-        assert_equal 'application/json', @response.content_type
-        assert_equal expected_return, response
+          assert_equal 'application/json', @response.content_type
+          assert_equal expected_return, response
+        end
       end
 
       def test_cache_expiration_on_update

test/test_helper.rb

@@ -1,5 +1,6 @@
 require 'bundler/setup'
 
+require 'timecop'
 require 'rails'
 require 'action_controller'
 require 'action_controller/test_case'