fixed multiple style guide violations

spec/controllers/code_ocean/files_controller_spec.rb

@@ -38,7 +38,7 @@ describe CodeOcean::FilesController do
     expect_assigns(file: CodeOcean::File)
 
     it 'destroys the file' do
-      exercise = FactoryGirl.create(:fibonacci)
+      FactoryGirl.create(:fibonacci)
       expect { request.call }.to change(CodeOcean::File, :count).by(-1)
     end
 

spec/controllers/execution_environments_controller_spec.rb

@@ -60,7 +60,7 @@ describe ExecutionEnvironmentsController do
     let(:command) { 'which ruby' }
 
     before(:each) do
-      expect(DockerClient).to receive(:new).with(execution_environment: execution_environment, user: user).and_call_original
+      expect(DockerClient).to receive(:new).with(execution_environment: execution_environment).and_call_original
       expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).with(command)
       post :execute_command, command: command, id: execution_environment.id
     end

spec/controllers/exercises_controller_spec.rb

@@ -30,7 +30,7 @@ describe ExercisesController do
       end
     end
 
-    context "with a file upload" do
+    context 'with a file upload' do
       let(:files_attributes) { {'0' => FactoryGirl.build(:file, content: fixture_file_upload('upload.rb', 'text/x-ruby')).attributes} }
       let(:request) { proc { post :create, exercise: exercise_attributes.merge(files_attributes: files_attributes) } }
 
@@ -144,7 +144,7 @@ describe ExercisesController do
 
       context 'when the score transmission succeeds' do
         before(:each) do
-          expect(controller).to receive(:send_score).and_return({status: 'success'})
+          expect(controller).to receive(:send_score).and_return(status: 'success')
           request
         end
 
@@ -160,7 +160,7 @@ describe ExercisesController do
 
       context 'when the score transmission fails' do
         before(:each) do
-          expect(controller).to receive(:send_score).and_return({status: 'unsupported'})
+          expect(controller).to receive(:send_score).and_return(status: 'unsupported')
           request
         end