use #described_class, as suggested by RuboCop

spec/models/code_ocean/file_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe CodeOcean::File do
-  let(:file) { CodeOcean::File.create.tap { |file| file.update(content: nil, hidden: nil, read_only: nil) } }
+  let(:file) { described_class.create.tap { |file| file.update(content: nil, hidden: nil, read_only: nil) } }
 
   it 'validates the presence of a file type' do
     expect(file.errors[:file_type_id]).to be_present

spec/models/consumer_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe Consumer do
-  let(:consumer) { Consumer.create }
+  let(:consumer) { described_class.create }
 
   it 'validates the presence of a name' do
     expect(consumer.errors[:name]).to be_present

spec/models/error_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe Error do
-  let(:error) { Error.create }
+  let(:error) { described_class.create }
 
   it 'validates the presence of an execution environment' do
     expect(error.errors[:execution_environment_id]).to be_present
@@ -13,7 +13,7 @@ describe Error do
 
   describe '.nested_resource?' do
     it 'is true' do
-      expect(Error.nested_resource?).to be true
+      expect(described_class.nested_resource?).to be true
     end
   end
 end

spec/models/execution_environment_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe ExecutionEnvironment do
-  let(:execution_environment) { ExecutionEnvironment.create }
+  let(:execution_environment) { described_class.create }
 
   it 'validates that the Docker image works', docker: true do
     expect(execution_environment).to receive(:validate_docker_image?).and_return(true)

spec/models/exercise_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe Exercise do
-  let(:exercise) { Exercise.create.tap { |exercise| exercise.update(public: nil, token: nil) } }
+  let(:exercise) { described_class.create.tap { |exercise| exercise.update(public: nil, token: nil) } }
 
   it 'validates the presence of a description' do
     expect(exercise.errors[:description]).to be_present

spec/models/external_user_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe ExternalUser do
-  let(:user) { ExternalUser.create }
+  let(:user) { described_class.create }
 
   it 'validates the presence of a consumer' do
     expect(user.errors[:consumer_id]).to be_present

spec/models/file_type_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe FileType do
-  let(:file_type) { FileType.create.tap { |file_type| file_type.update(binary: nil, executable: nil, renderable: nil) } }
+  let(:file_type) { described_class.create.tap { |file_type| file_type.update(binary: nil, executable: nil, renderable: nil) } }
 
   it 'validates the presence of the binary flag' do
     expect(file_type.errors[:binary]).to be_present

spec/models/hint_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe Hint do
-  let(:hint) { Hint.create }
+  let(:hint) { described_class.create }
 
   it 'validates the presence of an execution environment' do
     expect(hint.errors[:execution_environment_id]).to be_present
@@ -25,7 +25,7 @@ describe Hint do
 
   describe '.nested_resource?' do
     it 'is true' do
-      expect(Hint.nested_resource?).to be true
+      expect(described_class.nested_resource?).to be true
     end
   end
 

spec/models/internal_user_spec.rb

@@ -2,7 +2,7 @@ require 'rails_helper'
 
 describe InternalUser do
   let(:password) { SecureRandom.hex }
-  let(:user) { InternalUser.create }
+  let(:user) { described_class.create }
 
   it 'validates the presence of an email address' do
     expect(user.errors[:email]).to be_present
@@ -27,7 +27,7 @@ describe InternalUser do
   end
 
   context 'when not activated' do
-    let(:user) { InternalUser.create(FactoryGirl.attributes_for(:teacher, activation_state: 'pending', password: nil)) }
+    let(:user) { described_class.create(FactoryGirl.attributes_for(:teacher, activation_state: 'pending', password: nil)) }
 
     it 'validates the confirmation of the password' do
       user.update(password: password, password_confirmation: '')

spec/models/submission_spec.rb

@@ -6,16 +6,16 @@ describe Submission do
   end
 
   it 'validates the presence of a cause' do
-    expect(Submission.create.errors[:cause]).to be_present
+    expect(described_class.create.errors[:cause]).to be_present
   end
 
   it 'validates the presence of an exercise' do
-    expect(Submission.create.errors[:exercise_id]).to be_present
+    expect(described_class.create.errors[:exercise_id]).to be_present
   end
 
   it 'validates the presence of a user' do
-    expect(Submission.create.errors[:user_id]).to be_present
-    expect(Submission.create.errors[:user_type]).to be_present
+    expect(described_class.create.errors[:user_id]).to be_present
+    expect(described_class.create.errors[:user_type]).to be_present
   end
 
   %w(download render run test).each do |action|
@@ -35,7 +35,7 @@ describe Submission do
 
   describe '#to_s' do
     it "equals the class' model name" do
-      expect(@submission.to_s).to eq(Submission.model_name.human)
+      expect(@submission.to_s).to eq(described_class.model_name.human)
     end
   end
 end

spec/models/team_spec.rb

@@ -1,7 +1,7 @@
 require 'rails_helper'
 
 describe Team do
-  let(:team) { Team.create }
+  let(:team) { described_class.create }
 
   it 'validates the presence of a name' do
     expect(team.errors[:name]).to be_present