fixed multiple style guide violations

spec/models/code_ocean/file_spec.rb

@@ -21,7 +21,7 @@ describe CodeOcean::File do
 
   context 'as a teacher-defined test' do
     before(:each) { file.update(role: 'teacher_defined_test') }
-    
+
     it 'validates the presence of a feedback message' do
       expect(file.errors[:feedback_message]).to be_present
     end

spec/models/execution_environment_spec.rb

@@ -81,7 +81,7 @@ describe ExecutionEnvironment do
 
     context 'when the command produces an error' do
       it 'adds an error' do
-        expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_return({stderr: 'command not found'})
+        expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_return(stderr: 'command not found')
         working_docker_image?
         expect(execution_environment.errors[:docker_image]).to be_present
       end