diff --git a/lib/jsonapi/resources/railtie.rb b/lib/jsonapi/resources/railtie.rb
index 8e72eb01..43d9f5c3 100644
--- a/lib/jsonapi/resources/railtie.rb
+++ b/lib/jsonapi/resources/railtie.rb
@@ -6,6 +6,19 @@ class Railtie < ::Rails::Railtie
       rake_tasks do
         load 'tasks/check_upgrade.rake'
       end
+
+
+      initializer "jsonapi_resources.testing", after: :initialize do
+        next unless Rails.env.test?
+        # Make response.parsed_body work
+        ActionDispatch::IntegrationTest.register_encoder :api_json,
+          param_encoder: ->(params) {
+            params
+          },
+          response_parser: ->(body) {
+            JSONAPI::MimeTypes.parser.call(body)
+          }
+      end
     end
   end
 end
diff --git a/test/helpers/functional_helpers.rb b/test/helpers/functional_helpers.rb
index 3d6dc9d3..b3ce85f8 100644
--- a/test/helpers/functional_helpers.rb
+++ b/test/helpers/functional_helpers.rb
@@ -53,7 +53,7 @@ module FunctionalHelpers
     # end
     #
     def json_response
-      JSON.parse(@response.body)
+      @response.parsed_body
     end
   end
-end
\ No newline at end of file
+end
diff --git a/test/integration/requests/request_test.rb b/test/integration/requests/request_test.rb
index defe3619..52531514 100644
--- a/test/integration/requests/request_test.rb
+++ b/test/integration/requests/request_test.rb
@@ -73,13 +73,13 @@ def test_post_sessions
       'Accept' => JSONAPI::MEDIA_TYPE
     }
     assert_jsonapi_response 201
-    json_body = JSON.parse(response.body)
+    json_body = response.parsed_body
     session_id = json_body["data"]["id"]
 
     # Get what we just created
     get "/sessions/#{session_id}?include=responses"
     assert_jsonapi_response 200
-    json_body = JSON.parse(response.body)
+    json_body = response.parsed_body
 
     assert(json_body.is_a?(Object));
     assert(json_body["included"].is_a?(Array));
@@ -87,7 +87,7 @@ def test_post_sessions
 
     get "/sessions/#{session_id}?include=responses,responses.paragraph"
     assert_jsonapi_response 200
-    json_body = JSON.parse(response.body)
+    json_body = response.parsed_body
 
     assert_equal("single_textbox", json_body["included"][0]["attributes"]["response_type"]["single_textbox"]);
 
@@ -348,7 +348,7 @@ def test_post_polymorphic_with_has_many_relationship
 
     assert_jsonapi_response 201
 
-    body = JSON.parse(response.body)
+    body = response.parsed_body
     person = Person.find(body.dig("data", "id"))
 
     assert_equal "Reo", person.name
@@ -649,7 +649,7 @@ def test_patch_polymorphic_with_has_many_relationship
 
     assert_jsonapi_response 200
 
-    body = JSON.parse(response.body)
+    body = response.parsed_body
     person = Person.find(body.dig("data", "id"))
 
     assert_equal "Reo", person.name