diff --git a/spec/controllers/errors_controller_spec.rb b/spec/controllers/errors_controller_spec.rb
index 00b290bc..fe973448 100644
--- a/spec/controllers/errors_controller_spec.rb
+++ b/spec/controllers/errors_controller_spec.rb
@@ -29,7 +29,7 @@ describe ErrorsController do
           expect(response.body).to eq({hint: hint}.to_json)
         end
 
-        expect_content_type('application/json')
+        expect_json
         expect_status(200)
       end
 
@@ -46,7 +46,7 @@ describe ErrorsController do
           expect { request.call }.to change(Error, :count).by(1)
         end
 
-        expect_content_type('application/json')
+        expect_json
         expect_status(201)
       end
     end
@@ -55,7 +55,7 @@ describe ErrorsController do
       before(:each) { post :create, execution_environment_id: FactoryGirl.build(:error).execution_environment.id, error: {}, format: :json }
 
       expect_assigns(error: Error)
-      expect_content_type('application/json')
+      expect_json
       expect_status(422)
     end
   end
diff --git a/spec/controllers/execution_environments_controller_spec.rb b/spec/controllers/execution_environments_controller_spec.rb
index 7e380008..ba105d39 100644
--- a/spec/controllers/execution_environments_controller_spec.rb
+++ b/spec/controllers/execution_environments_controller_spec.rb
@@ -67,7 +67,7 @@ describe ExecutionEnvironmentsController do
 
     expect_assigns(docker_client: DockerClient)
     expect_assigns(execution_environment: :execution_environment)
-    expect_content_type('application/json')
+    expect_json
     expect_status(200)
   end
 
diff --git a/spec/controllers/exercises_controller_spec.rb b/spec/controllers/exercises_controller_spec.rb
index 9302b983..4513b319 100644
--- a/spec/controllers/exercises_controller_spec.rb
+++ b/spec/controllers/exercises_controller_spec.rb
@@ -154,7 +154,7 @@ describe ExercisesController do
           expect(assigns(:submission)).to be_a(Submission)
         end
 
-        expect_content_type('application/json')
+        expect_json
         expect_status(200)
       end
 
@@ -170,7 +170,7 @@ describe ExercisesController do
           expect(assigns(:submission)).to be_a(Submission)
         end
 
-        expect_content_type('application/json')
+        expect_json
         expect_status(503)
       end
     end
@@ -188,7 +188,7 @@ describe ExercisesController do
         expect(assigns(:submission)).to be_a(Submission)
       end
 
-      expect_content_type('application/json')
+      expect_json
       expect_status(200)
     end
   end
diff --git a/spec/controllers/submissions_controller_spec.rb b/spec/controllers/submissions_controller_spec.rb
index b47edf59..285070ef 100644
--- a/spec/controllers/submissions_controller_spec.rb
+++ b/spec/controllers/submissions_controller_spec.rb
@@ -21,7 +21,7 @@ describe SubmissionsController do
         expect { request.call }.to change(Submission, :count).by(1)
       end
 
-      expect_content_type('application/json')
+      expect_json
       expect_status(201)
     end
 
@@ -29,7 +29,7 @@ describe SubmissionsController do
       before(:each) { post :create, submission: {} }
 
       expect_assigns(submission: Submission)
-      expect_content_type('application/json')
+      expect_json
       expect_status(422)
     end
   end
@@ -169,7 +169,7 @@ describe SubmissionsController do
 
     expect_assigns(docker_client: DockerClient)
     expect_assigns(submission: :submission)
-    expect_content_type('application/json')
+    expect_json
     expect_status(200)
   end
 end
diff --git a/spec/support/controllers.rb b/spec/support/controllers.rb
index d5a18a08..cc9a5dd9 100644
--- a/spec/support/controllers.rb
+++ b/spec/support/controllers.rb
@@ -27,6 +27,10 @@ def expect_flash_message(type, message)
   end
 end
 
+def expect_json
+  expect_content_type('application/json')
+end
+
 def expect_redirect(path = nil)
   if path
     it "redirects to #{path}" do