diff --git a/spec/concerns/submission_scoring_spec.rb b/spec/concerns/submission_scoring_spec.rb
index cc30fe56..c1394b92 100644
--- a/spec/concerns/submission_scoring_spec.rb
+++ b/spec/concerns/submission_scoring_spec.rb
@@ -5,12 +5,15 @@ class Controller < AnonymousController
 end
 
 describe SubmissionScoring do
+  before(:all) do
+    @submission = FactoryGirl.create(:submission, cause: 'submit')
+  end
+
   let(:controller) { Controller.new }
-  let(:submission) { FactoryGirl.create(:submission, cause: 'submit') }
   before(:each) { controller.instance_variable_set(:@current_user, FactoryGirl.create(:external_user)) }
 
   describe '#score_submission' do
-    let(:score_submission) { Proc.new { controller.score_submission(submission) } }
+    let(:score_submission) { Proc.new { controller.score_submission(@submission) } }
     before(:each) { score_submission.call }
 
     it 'assigns @assessor' do
@@ -22,14 +25,14 @@ describe SubmissionScoring do
     end
 
     it 'executes the teacher-defined test cases' do
-      submission.collect_files.select(&:teacher_defined_test?).each do |file|
-        expect_any_instance_of(DockerClient).to receive(:execute_test_command).with(submission, file.name_with_extension).and_return({})
+      @submission.collect_files.select(&:teacher_defined_test?).each do |file|
+        expect_any_instance_of(DockerClient).to receive(:execute_test_command).with(@submission, file.name_with_extension).and_return({})
       end
       score_submission.call
     end
 
     it 'updates the submission' do
-      expect(submission).to receive(:update).with(score: anything)
+      expect(@submission).to receive(:update).with(score: anything)
       score_submission.call
     end
   end
diff --git a/spec/controllers/errors_controller_spec.rb b/spec/controllers/errors_controller_spec.rb
index efbe3d1a..e760f2ed 100644
--- a/spec/controllers/errors_controller_spec.rb
+++ b/spec/controllers/errors_controller_spec.rb
@@ -61,7 +61,7 @@ describe ErrorsController do
   end
 
   describe 'GET #index' do
-    let!(:errors) { FactoryGirl.create_pair(:error) }
+    before(:all) { FactoryGirl.create_pair(:error) }
     before(:each) { get :index, execution_environment_id: execution_environment.id }
 
     expect_assigns(execution_environment: :execution_environment)
diff --git a/spec/controllers/execution_environments_controller_spec.rb b/spec/controllers/execution_environments_controller_spec.rb
index 7f195b28..27be49e3 100644
--- a/spec/controllers/execution_environments_controller_spec.rb
+++ b/spec/controllers/execution_environments_controller_spec.rb
@@ -72,7 +72,7 @@ describe ExecutionEnvironmentsController do
   end
 
   describe 'GET #index' do
-    let!(:execution_environments) { FactoryGirl.create_pair(:ruby) }
+    before(:all) { FactoryGirl.create_pair(:ruby) }
     before(:each) { get :index }
 
     expect_assigns(execution_environments: ExecutionEnvironment.all)
diff --git a/spec/controllers/exercises_controller_spec.rb b/spec/controllers/exercises_controller_spec.rb
index ceda5a25..9302b983 100644
--- a/spec/controllers/exercises_controller_spec.rb
+++ b/spec/controllers/exercises_controller_spec.rb
@@ -1,12 +1,12 @@
 require 'rails_helper'
 
 describe ExercisesController do
-  let(:exercise) { FactoryGirl.create(:fibonacci) }
+  let(:exercise) { FactoryGirl.create(:dummy) }
   let(:user) { FactoryGirl.create(:admin) }
   before(:each) { allow(controller).to receive(:current_user).and_return(user) }
 
   describe 'POST #create' do
-    let(:exercise_attributes) { FactoryGirl.build(:fibonacci).attributes }
+    let(:exercise_attributes) { FactoryGirl.build(:dummy).attributes }
 
     context 'with a valid exercise' do
       let(:request) { Proc.new { post :create, exercise: exercise_attributes } }
@@ -61,7 +61,7 @@ describe ExercisesController do
     expect_assigns(exercise: :exercise)
 
     it 'destroys the exercise' do
-      exercise = FactoryGirl.create(:fibonacci)
+      exercise = FactoryGirl.create(:dummy)
       expect { delete :destroy, id: exercise.id }.to change(Exercise, :count).by(-1)
     end
 
@@ -102,8 +102,8 @@ describe ExercisesController do
   end
 
   describe 'GET #index' do
-    let!(:exercises) { FactoryGirl.create_pair(:fibonacci) }
     let(:scope) { Pundit.policy_scope!(user, Exercise) }
+    before(:all) { FactoryGirl.create_pair(:dummy) }
     before(:each) { get :index }
 
     expect_assigns(exercises: :scope)
@@ -195,7 +195,7 @@ describe ExercisesController do
 
   describe 'PUT #update' do
     context 'with a valid exercise' do
-      let(:exercise_attributes) { FactoryGirl.build(:fibonacci).attributes }
+      let(:exercise_attributes) { FactoryGirl.build(:dummy).attributes }
       before(:each) { put :update, exercise: exercise_attributes, id: exercise.id }
 
       expect_assigns(exercise: Exercise)
diff --git a/spec/controllers/file_types_controller_spec.rb b/spec/controllers/file_types_controller_spec.rb
index 5da53424..ed8ca675 100644
--- a/spec/controllers/file_types_controller_spec.rb
+++ b/spec/controllers/file_types_controller_spec.rb
@@ -53,7 +53,7 @@ describe FileTypesController do
   end
 
   describe 'GET #index' do
-    let!(:file_types) { FactoryGirl.create_pair(:dot_rb) }
+    before(:all) { FactoryGirl.create_pair(:dot_rb) }
     before(:each) { get :index }
 
     expect_assigns(file_types: FileType.all)
diff --git a/spec/controllers/hints_controller_spec.rb b/spec/controllers/hints_controller_spec.rb
index a881c643..7c47fc8a 100644
--- a/spec/controllers/hints_controller_spec.rb
+++ b/spec/controllers/hints_controller_spec.rb
@@ -55,7 +55,7 @@ describe HintsController do
   end
 
   describe 'GET #index' do
-    let!(:hints) { FactoryGirl.create_pair(:ruby_syntax_error) }
+    before(:all) { FactoryGirl.create_pair(:ruby_syntax_error) }
     before(:each) { get :index, execution_environment_id: execution_environment.id }
 
     expect_assigns(execution_environment: :execution_environment)
diff --git a/spec/controllers/sessions_controller_spec.rb b/spec/controllers/sessions_controller_spec.rb
index 4012d5ee..79f53566 100644
--- a/spec/controllers/sessions_controller_spec.rb
+++ b/spec/controllers/sessions_controller_spec.rb
@@ -27,7 +27,7 @@ describe SessionsController do
   end
 
   describe 'POST #create_through_lti' do
-    let(:exercise) { FactoryGirl.create(:fibonacci) }
+    let(:exercise) { FactoryGirl.create(:dummy) }
     let(:nonce) { SecureRandom.hex }
 
     context 'without OAuth parameters' do
@@ -125,7 +125,7 @@ describe SessionsController do
 
   describe 'GET #destroy_through_lti' do
     let(:request) { Proc.new { get :destroy_through_lti, consumer_id: consumer.id, submission_id: submission.id } }
-    let(:submission) { FactoryGirl.create(:submission) }
+    let(:submission) { FactoryGirl.create(:submission, exercise: FactoryGirl.create(:dummy)) }
 
     before(:each) do
       session[:consumer_id] = consumer.id
diff --git a/spec/controllers/submissions_controller_spec.rb b/spec/controllers/submissions_controller_spec.rb
index 10c9c600..b47edf59 100644
--- a/spec/controllers/submissions_controller_spec.rb
+++ b/spec/controllers/submissions_controller_spec.rb
@@ -57,7 +57,7 @@ describe SubmissionsController do
   end
 
   describe 'GET #index' do
-    let!(:submissions) { FactoryGirl.create_pair(:submission) }
+    before(:all) { FactoryGirl.create_pair(:submission) }
     before(:each) { get :index }
 
     expect_assigns(submissions: Submission.all)
diff --git a/spec/controllers/teams_controller_spec.rb b/spec/controllers/teams_controller_spec.rb
index 8c817b2c..dc823afe 100644
--- a/spec/controllers/teams_controller_spec.rb
+++ b/spec/controllers/teams_controller_spec.rb
@@ -50,7 +50,7 @@ describe TeamsController do
   end
 
   describe 'GET #index' do
-    let!(:teams) { FactoryGirl.create_pair(:team) }
+    before(:all) { FactoryGirl.create_pair(:team) }
     before(:each) { get :index }
 
     expect_assigns(teams: Team.all)
diff --git a/spec/factories/exercise.rb b/spec/factories/exercise.rb
index 6d009e41..dbbacd57 100644
--- a/spec/factories/exercise.rb
+++ b/spec/factories/exercise.rb
@@ -32,6 +32,14 @@ FactoryGirl.define do
     end
   end
 
+  factory :dummy, class: Exercise do
+    created_by_teacher
+    description 'Dummy'
+    association :execution_environment, factory: :ruby
+    instructions
+    title 'Dummy'
+  end
+
   factory :even_odd, class: Exercise do
     created_by_teacher
     description 'Implement two methods even and odd which return whether a given number is even or odd, respectively.'
diff --git a/spec/models/submission_spec.rb b/spec/models/submission_spec.rb
index ffdd14a0..a66f361e 100644
--- a/spec/models/submission_spec.rb
+++ b/spec/models/submission_spec.rb
@@ -1,29 +1,30 @@
 require 'rails_helper'
 
 describe Submission do
-  let(:submission) { Submission.create }
+  before(:all) do
+    @submission = FactoryGirl.create(:submission)
+  end
 
   it 'validates the presence of a cause' do
-    expect(submission.errors[:cause]).to be_present
+    expect(Submission.create.errors[:cause]).to be_present
   end
 
   it 'validates the presence of an exercise' do
-    expect(submission.errors[:exercise_id]).to be_present
+    expect(Submission.create.errors[:exercise_id]).to be_present
   end
 
   it 'validates the presence of a user' do
-    expect(submission.errors[:user_id]).to be_present
-    expect(submission.errors[:user_type]).to be_present
+    expect(Submission.create.errors[:user_id]).to be_present
+    expect(Submission.create.errors[:user_type]).to be_present
   end
 
   %w[download render run test].each do |action|
     describe "##{action}_url" do
-      let(:submission) { FactoryGirl.create(:submission) }
-      let(:url) { submission.send(:"#{action}_url") }
+      let(:url) { @submission.send(:"#{action}_url") }
 
       it "starts like the #{action} path" do
         filename = File.basename(__FILE__)
-        expect(url).to start_with(Rails.application.routes.url_helpers.send(:"#{action}_submission_path", submission, filename).sub(filename, ''))
+        expect(url).to start_with(Rails.application.routes.url_helpers.send(:"#{action}_submission_path", @submission, filename).sub(filename, ''))
       end
 
       it 'ends with a placeholder' do
diff --git a/spec/policies/code_ocean/file_policy_spec.rb b/spec/policies/code_ocean/file_policy_spec.rb
index fd467f83..80e5ad53 100644
--- a/spec/policies/code_ocean/file_policy_spec.rb
+++ b/spec/policies/code_ocean/file_policy_spec.rb
@@ -3,39 +3,41 @@ require 'rails_helper'
 describe CodeOcean::FilePolicy do
   subject { CodeOcean::FilePolicy }
 
-  let(:file) { FactoryGirl.build(:file) }
-  let(:exercise) { FactoryGirl.create(:fibonacci) }
-  let(:submission) { FactoryGirl.create(:submission) }
-
   permissions :create? do
     context 'as part of an exercise' do
-      before(:each) { file.context = exercise }
+      before(:all) do
+        @exercise = FactoryGirl.create(:fibonacci)
+        @file = @exercise.files.first
+      end
 
       it 'grants access to admins' do
-        expect(subject).to permit(FactoryGirl.build(:admin), file)
+        expect(subject).to permit(FactoryGirl.build(:admin), @file)
       end
 
       it 'grants access to authors' do
-        expect(subject).to permit(exercise.author, file)
+        expect(subject).to permit(@exercise.author, @file)
       end
 
       it 'does not grant access to all other users' do
         [:external_user, :teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryGirl.build(factory_name), file)
+          expect(subject).not_to permit(FactoryGirl.build(factory_name), @file)
         end
       end
     end
 
     context 'as part of a submission' do
-      before(:each) { file.context = submission }
+      before(:all) do
+        @submission = FactoryGirl.create(:submission)
+        @file = @submission.files.first
+      end
 
       it 'grants access to authors' do
-        expect(subject).to permit(submission.author, file)
+        expect(subject).to permit(@submission.author, @file)
       end
 
       it 'does not grant access to all other users' do
         [:admin, :external_user, :teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryGirl.build(factory_name), file)
+          expect(subject).not_to permit(FactoryGirl.build(factory_name), @file)
         end
       end
     end
@@ -43,29 +45,34 @@ describe CodeOcean::FilePolicy do
 
   permissions :destroy? do
     context 'as part of an exercise' do
-      before(:each) { file.context = exercise }
+      before(:all) do
+        @exercise = FactoryGirl.create(:fibonacci)
+        @file = @exercise.files.first
+      end
 
       it 'grants access to admins' do
-        expect(subject).to permit(FactoryGirl.build(:admin), file)
+        expect(subject).to permit(FactoryGirl.build(:admin), @file)
       end
 
       it 'grants access to authors' do
-        expect(subject).to permit(exercise.author, file)
+        expect(subject).to permit(@exercise.author, @file)
       end
 
       it 'does not grant access to all other users' do
         [:external_user, :teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryGirl.build(factory_name), file)
+          expect(subject).not_to permit(FactoryGirl.build(factory_name), @file)
         end
       end
     end
 
     context 'as part of a submission' do
-      before(:each) { file.context = submission }
+      before(:all) do
+        @file = FactoryGirl.create(:submission).files.first
+      end
 
       it 'does not grant access to anyone' do
         [:admin, :external_user, :teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryGirl.build(factory_name), file)
+          expect(subject).not_to permit(FactoryGirl.build(factory_name), @file)
         end
       end
     end
diff --git a/spec/policies/exercise_policy_spec.rb b/spec/policies/exercise_policy_spec.rb
index e11a06f3..624c93f8 100644
--- a/spec/policies/exercise_policy_spec.rb
+++ b/spec/policies/exercise_policy_spec.rb
@@ -4,7 +4,7 @@ describe ExercisePolicy do
   subject { ExercisePolicy }
 
   before(:all) do
-    @exercise = FactoryGirl.build(:fibonacci, team: FactoryGirl.create(:team))
+    @exercise = FactoryGirl.build(:dummy, team: FactoryGirl.create(:team))
   end
 
   [:create?, :index?, :new?].each do |action|
@@ -67,7 +67,7 @@ describe ExercisePolicy do
         [@admin, @teacher].each do |user|
           [true, false].each do |public|
             [@team, nil].each do |team|
-              FactoryGirl.create(:fibonacci, public: public, team: team, user_id: user.id, user_type: InternalUser.class.name)
+              FactoryGirl.create(:dummy, public: public, team: team, user_id: user.id, user_type: InternalUser.class.name)
             end
           end
         end
diff --git a/spec/policies/submission_policy_spec.rb b/spec/policies/submission_policy_spec.rb
index d036696a..d04059a7 100644
--- a/spec/policies/submission_policy_spec.rb
+++ b/spec/policies/submission_policy_spec.rb
@@ -19,7 +19,7 @@ describe SubmissionPolicy do
 
       it 'grants access to authors' do
         user = FactoryGirl.create(:external_user)
-        expect(subject).to permit(user, FactoryGirl.build(:submission, user_id: user.id, user_type: user.class.name))
+        expect(subject).to permit(user, FactoryGirl.build(:submission, exercise: Exercise.new, user_id: user.id, user_type: user.class.name))
       end
     end
   end