Apply manual rubocop fixes

2021-05-14 11:07:11 +02:00
parent 6cbecb5b39
commit da0a682ffb
109 changed files with 431 additions and 416 deletions
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@ -6,7 +6,7 @@ class ApplicationController < ActionController::Base

  MEMBER_ACTIONS = %i[destroy edit show update].freeze

-  after_action :verify_authorized, except: %i[help welcome]
+  after_action :verify_authorized, except: %i[welcome]
  around_action :mnemosyne_trace
  before_action :set_sentry_context, :set_locale, :allow_iframe_requests, :load_embed_options
  protect_from_forgery(with: :exception, prepend: true)
--- a/app/controllers/code_ocean/files_controller.rb
+++ b/app/controllers/code_ocean/files_controller.rb
@ -31,7 +31,10 @@ module CodeOcean
 path: path, status: :created)
        else
          filename = "#{@object.path || ''}/#{@object.name || ''}#{@object.file_type.try(:file_extension) || ''}"
-          format.html { redirect_to(options[:path]); flash[:danger] = t('files.error.filename', name: filename) }
+          format.html do
+            flash[:danger] = t('files.error.filename', name: filename)
+            redirect_to(options[:path])
+          end
          format.json { render(json: @object.errors, status: :unprocessable_entity) }
        end
      end
--- a/app/controllers/codeharbor_links_controller.rb
+++ b/app/controllers/codeharbor_links_controller.rb
@ -3,7 +3,7 @@
 class CodeharborLinksController < ApplicationController
  include CommonBehavior
  before_action :verify_codeharbor_activation
-  before_action :set_codeharbor_link, only: %i[show edit update destroy]
+  before_action :set_codeharbor_link, only: %i[edit update destroy]

  def new
    base_url = CodeOcean::Config.new(:code_ocean).read[:codeharbor][:url] || ''
--- a/app/controllers/comments_controller.rb
+++ b/app/controllers/comments_controller.rb
@ -1,7 +1,7 @@
 # frozen_string_literal: true

 class CommentsController < ApplicationController
-  before_action :set_comment, only: %i[show edit update destroy]
+  before_action :set_comment, only: %i[show update destroy]

  # to disable authorization check: comment the line below back in
  # skip_after_action :verify_authorized
--- a/app/controllers/concerns/lti.rb
+++ b/app/controllers/concerns/lti.rb
@ -60,11 +60,9 @@ module Lti
    if provider.roles.present?
      provider.roles.each do |role|
        case role.downcase
-          when 'administrator'
+          when 'administrator', 'instructor'
            # We don't want anyone to get admin privileges through LTI
            result = 'teacher' if result == 'learner'
-          when 'instructor'
-            result = 'teacher' if result == 'learner'
          else # 'learner'
            next
        end
@ -172,8 +170,7 @@ module Lti
        normalized_lit_score *= 0.0
      end
      response = provider.post_replace_result!(normalized_lit_score)
-      {code: response.response_code, message: response.post_response.body, status: response.code_major,
-score_sent: normalized_lit_score}
+      {code: response.response_code, message: response.post_response.body, status: response.code_major, score_sent: normalized_lit_score}
    else
      {status: 'unsupported'}
    end
--- a/app/controllers/concerns/remote_evaluation_parameters.rb
+++ b/app/controllers/concerns/remote_evaluation_parameters.rb
@ -5,8 +5,7 @@ module RemoteEvaluationParameters

  def remote_evaluation_params
    if params[:remote_evaluation].present?
-      remote_evaluation_params = params[:remote_evaluation].permit(:validation_token,
-        files_attributes: file_attributes)
+      params[:remote_evaluation].permit(:validation_token, files_attributes: file_attributes)
    end
  end
  private :remote_evaluation_params
--- a/app/controllers/concerns/submission_scoring.rb
+++ b/app/controllers/concerns/submission_scoring.rb
@ -81,7 +81,7 @@ module SubmissionScoring
      end
    end
    submission.update(score: score)
-    if submission.normalized_score == 1.0
+    if submission.normalized_score.to_d == 1.0.to_d
      Thread.new do
        RequestForComment.where(exercise_id: submission.exercise_id, user_id: submission.user_id,
 user_type: submission.user_type).each do |rfc|
--- a/app/controllers/exercise_collections_controller.rb
+++ b/app/controllers/exercise_collections_controller.rb
@ -58,8 +58,8 @@ class ExerciseCollectionsController < ApplicationController
                       end
    sanitized_params[:exercise_ids] = sanitized_params[:exercise_ids].reject {|v| v.nil? or v == '' }
    sanitized_params.tap do |p|
-      p[:exercise_collection_items] = p[:exercise_ids].map.with_index do |_id, index|
-        ExerciseCollectionItem.find_or_create_by(exercise_id: _id, exercise_collection_id: @exercise_collection.id, position: index)
+      p[:exercise_collection_items] = p[:exercise_ids].map.with_index do |id, index|
+        ExerciseCollectionItem.find_or_create_by(exercise_id: id, exercise_collection_id: @exercise_collection.id, position: index)
      end
      p.delete(:exercise_ids)
    end
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@ -61,7 +61,7 @@ raise: false
  def collect_paths(files)
    unique_paths = files.map(&:path).reject(&:blank?).uniq
    subpaths = unique_paths.map do |path|
-      (path.split('/').length + 1).times.map do |n|
+      Array.new((path.split('/').length + 1)) do |n|
        path.split('/').shift(n).join('/')
      end
    end
@ -271,7 +271,7 @@ user_id: current_user.id, user_type: current_user.class.name
  def implement
    redirect_to(@exercise, alert: t('exercises.implement.unpublished')) if @exercise.unpublished? && current_user.role != 'admin' && current_user.role != 'teacher' # TODO: TESTESTEST
    redirect_to(@exercise, alert: t('exercises.implement.no_files')) unless @exercise.files.visible.exists?
-    user_solved_exercise = @exercise.has_user_solved(current_user)
+    user_solved_exercise = @exercise.solved_by?(current_user)
    count_interventions_today = UserExerciseIntervention.where(user: current_user).where('created_at >= ?',
      Time.zone.now.beginning_of_day).count
    user_got_intervention_in_exercise = UserExerciseIntervention.where(user: current_user,
@ -280,11 +280,10 @@ exercise: @exercise).size >= max_intervention_count_per_exercise

    if @embed_options[:disable_interventions]
      @show_rfc_interventions = false
-      @show_break_interventions = false
    else
      @show_rfc_interventions = (!user_solved_exercise && !user_got_enough_interventions).to_s
-      @show_break_interventions = false
    end
+    @show_break_interventions = false

    @hide_rfc_button = @embed_options[:disable_rfc]

@ -308,9 +307,7 @@ exercise: @exercise).size >= max_intervention_count_per_exercise
      lti_json = lti_parameters.lti_parameters['launch_presentation_return_url']

      @course_token =
-        if lti_json.nil?
-          ''
-        elsif match = lti_json.match(%r{^.*courses/([a-z0-9\-]+)/sections})
+        if lti_json.present? && (match = lti_json.match(%r{^.*courses/([a-z0-9\-]+)/sections}))
          match.captures.first
        else
          ''
@ -470,7 +467,7 @@ working_time_accumulated: working_time_accumulated})
      authorize(@external_user, :statistics?)
      if policy(@exercise).detailed_statistics?
        @submissions = Submission.where(user: @external_user,
-exercise_id: @exercise.id).in_study_group_of(current_user).order('created_at')
+          exercise_id: @exercise.id).in_study_group_of(current_user).order('created_at')
        interventions = UserExerciseIntervention.where('user_id = ?  AND exercise_id = ?', @external_user.id,
          @exercise.id)
        @all_events = (@submissions + interventions).sort_by(&:created_at)
@ -480,11 +477,11 @@ exercise_id: @exercise.id).in_study_group_of(current_user).order('created_at')
        end
        @working_times_until = []
        @all_events.each_with_index do |_, index|
-          @working_times_until.push((format_time_difference(@deltas[0..index].inject(:+)) if index.positive?))
+          @working_times_until.push((format_time_difference(@deltas[0..index].sum) if index.positive?))
        end
      else
        final_submissions = Submission.where(user: @external_user,
-exercise_id: @exercise.id).in_study_group_of(current_user).final
+          exercise_id: @exercise.id).in_study_group_of(current_user).final
        @submissions = []
        %i[before_deadline within_grace_period after_late_deadline].each do |filter|
          relevant_submission = final_submissions.send(filter).latest
@ -570,7 +567,7 @@ normalized_score: @submission.normalized_score})

  def redirect_after_submit
    Rails.logger.debug("Redirecting user with score:s #{@submission.normalized_score}")
-    if @submission.normalized_score == 1.0
+    if @submission.normalized_score.to_d == 1.0.to_d
      # if user is external and has an own rfc, redirect to it and message him to clean up and accept the answer. (we need to check that the user is external,
      # otherwise an internal user could be shown a false rfc here, since current_user.id is polymorphic, but only makes sense for external users when used with rfcs.)
      # redirect 10 percent pseudorandomly to the feedback page
@ -603,7 +600,7 @@ normalized_score: @submission.normalized_score})
          flash.keep(:notice)

          # increase counter 'times_featured' in rfc
-          rfc.increment!(:times_featured)
+          rfc.increment(:times_featured)

          clear_lti_session_data(@submission.exercise_id, @submission.user_id)
          respond_to do |format|
--- a/app/controllers/flowr_controller.rb
+++ b/app/controllers/flowr_controller.rb
@ -23,7 +23,7 @@ class FlowrController < ApplicationController
    # for each error get all attributes, filter out uninteresting ones, and build a query
    insights = errors.map do |error|
      attributes = error.structured_error_attributes.select do |attribute|
-        is_interesting(attribute) and attribute.match
+        interesting?(attribute) and attribute.match
      end
      # once the programming language model becomes available, the language name can be added to the query to
      # produce more relevant results
@ -35,8 +35,8 @@ class FlowrController < ApplicationController
    render json: insights, status: :ok
  end

-  def is_interesting(attribute)
-    attribute.error_template_attribute.key.index(/error message|error type/i) != nil
+  def interesting?(attribute)
+    !attribute.error_template_attribute.key.index(/error message|error type/i).nil?
  end
-  private :is_interesting
+  private :interesting?
 end
--- a/app/controllers/request_for_comments_controller.rb
+++ b/app/controllers/request_for_comments_controller.rb
@ -6,7 +6,7 @@ class RequestForCommentsController < ApplicationController
  before_action :require_user!
  before_action :set_request_for_comment, only: %i[show mark_as_solved set_thank_you_note]
  before_action :set_study_group_grouping,
-    only: %i[index get_my_comment_requests get_rfcs_with_my_comments get_rfcs_for_exercise]
+    only: %i[index my_comment_requests rfcs_with_my_comments rfcs_for_exercise]

  def authorize!
    authorize(@request_for_comments || @request_for_comment)
@ -31,7 +31,7 @@ class RequestForCommentsController < ApplicationController
  end

  # GET /my_request_for_comments
-  def get_my_comment_requests
+  def my_comment_requests
    @search = RequestForComment
      .with_last_activity
      .where(user: current_user)
@ -44,7 +44,7 @@ class RequestForCommentsController < ApplicationController
  end

  # GET /my_rfc_activity
-  def get_rfcs_with_my_comments
+  def rfcs_with_my_comments
    @search = RequestForComment
      .with_last_activity
      .joins(:comments) # we don't need to outer join here, because we know the user has commented on these
@ -58,7 +58,7 @@ class RequestForCommentsController < ApplicationController
  end

  # GET /exercises/:id/request_for_comments
-  def get_rfcs_for_exercise
+  def rfcs_for_exercise
    exercise = Exercise.find(params[:exercise_id])
    @search = RequestForComment
      .with_last_activity
--- a/app/controllers/submissions_controller.rb
+++ b/app/controllers/submissions_controller.rb
@ -9,7 +9,7 @@ class SubmissionsController < ApplicationController
  include Tubesock::Hijack

  before_action :set_submission,
-    only: %i[download download_file render_file run score extract_errors show statistics stop test]
+    only: %i[download download_file render_file run score extract_errors show statistics test]
  before_action :set_docker_client, only: %i[run test]
  before_action :set_files, only: %i[download download_file render_file show run]
  before_action :set_file, only: %i[download_file render_file run]
@ -199,7 +199,7 @@ user_type: current_user.class.name, row: annotation[1][:row], column: annotation
              socket.send data
              Rails.logger.debug("Sent the received client data to docker:#{data}")
            end
-          rescue JSON::ParserError => e
+          rescue JSON::ParserError
            socket.send data
            Rails.logger.debug("Rescued parsing error, sent the received client data to docker:#{data}")
            Sentry.set_extras(data: data)
@ -266,7 +266,7 @@ user_type: current_user.class.name, row: annotation[1][:row], column: annotation
    end
  end

-  def parse_message(message, output_stream, socket, container = nil, recursive = true)
+  def parse_message(message, output_stream, socket, container = nil, recursive: true)
    parsed = ''
    begin
      parsed = JSON.parse(message)
@ -279,11 +279,11 @@ user_type: current_user.class.name, row: annotation[1][:row], column: annotation
        socket.send_data JSON.dump(parsed)
        Rails.logger.info("parse_message sent: #{JSON.dump(parsed)}")
      end
-    rescue JSON::ParserError => e
+    rescue JSON::ParserError
      # Check wether the message contains multiple lines, if true try to parse each line
      if recursive && message.include?("\n")
        message.split("\n").each do |part|
-          parse_message(part, output_stream, socket, container, false)
+          parse_message(part, output_stream, socket, container, recursive: false)
        end
      elsif message.include?('<img') || message.start_with?('{"cmd') || message.include?('"turtlebatch"')
        # Rails.logger.info('img foung')
--- a/app/controllers/user_exercise_feedbacks_controller.rb
+++ b/app/controllers/user_exercise_feedbacks_controller.rb
@ -39,7 +39,7 @@ class UserExerciseFeedbacksController < ApplicationController
      authorize!
      if validate_inputs(uef_params)
        path =
-          if rfc && submission && submission.normalized_score == 1.0
+          if rfc && submission && submission.normalized_score.to_d == 1.0.to_d
            request_for_comment_path(rfc)
          else
            implement_exercise_path(@exercise)
@ -82,7 +82,7 @@ class UserExerciseFeedbacksController < ApplicationController
    authorize!
    if @exercise && validate_inputs(uef_params)
      path =
-        if rfc && submission && submission.normalized_score == 1.0
+        if rfc && submission && submission.normalized_score.to_d == 1.0.to_d
          request_for_comment_path(rfc)
        else
          implement_exercise_path(@exercise)
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@ -42,7 +42,9 @@ module ApplicationHelper
  end

  def render_markdown(markdown)
+    # rubocop:disable Rails/OutputSafety
    Kramdown::Document.new(markdown).to_html.html_safe
+    # rubocop:enable Rails/OutputSafety
  end

  def row(options = {}, &block)
--- a/app/mailers/application_mailer.rb
+++ b/app/mailers/application_mailer.rb
@ -0,0 +1,4 @@
+# frozen_string_literal: true
+
+class ApplicationMailer < ActionMailer::Base
+end
--- a/app/models/concerns/default_values.rb
+++ b/app/models/concerns/default_values.rb
@ -1,10 +1,12 @@
 # frozen_string_literal: true

 module DefaultValues
+  # rubocop:disable Naming/AccessorMethodName
  def set_default_values_if_present(options = {})
    options.each do |attribute, value|
      send(:"#{attribute}=", send(:"#{attribute}") || value) if has_attribute?(attribute)
    end
  end
  private :set_default_values_if_present
+  # rubocop:enable Naming/AccessorMethodName
 end
--- a/app/models/exercise.rb
+++ b/app/models/exercise.rb
@ -49,7 +49,7 @@ class Exercise < ApplicationRecord
  MAX_GROUP_EXERCISE_FEEDBACKS = 20

  def average_percentage
-    if average_score && (maximum_score != 0.0) && submissions.exists?(cause: 'submit')
+    if average_score && (maximum_score.to_d != 0.0.to_d) && submissions.exists?(cause: 'submit')
      (average_score / maximum_score * 100).round(2)
    else
      0
@ -477,7 +477,6 @@ class Exercise < ApplicationRecord
      return 'reference_implementation'
    elsif (file_class == 'template') && (comment == 'main')
      return 'main_file'
-    elsif (file_class == 'internal') && (comment == 'main')
    end

    'regular_file'
@ -536,7 +535,7 @@ class Exercise < ApplicationRecord
    submissions.final.where(user_id: user.id, user_type: user.class.name).order(created_at: :desc).first
  end

-  def has_user_solved(user)
+  def solved_by?(user)
    maximum_score(user).to_i == maximum_score.to_i
  end

@ -579,7 +578,7 @@ cause: %w[submit assess remoteSubmit remoteAssess]}).distinct
  private :valid_submission_deadlines?

  def needs_more_feedback?(submission)
-    if submission.normalized_score == 1.00
+    if submission.normalized_score.to_d == 1.0.to_d
      user_exercise_feedbacks.final.size <= MAX_GROUP_EXERCISE_FEEDBACKS
    else
      user_exercise_feedbacks.intermediate.size <= MAX_GROUP_EXERCISE_FEEDBACKS
--- a/app/models/exercise_collection.rb
+++ b/app/models/exercise_collection.rb
@ -23,8 +23,8 @@ working_time: time_to_f(item.exercise.average_working_time)}
      0
    else
      values = collection_statistics.values.reject {|o| o[:working_time].nil? }
-      sum = values.reduce(0) {|sum, item| sum + item[:working_time] }
-      sum / values.size
+      total_sum = values.reduce(0) {|sum, item| sum + item[:working_time] }
+      total_sum / values.size
    end
  end

--- a/app/models/intervention.rb
+++ b/app/models/intervention.rb
@ -8,7 +8,7 @@ class Intervention < ApplicationRecord
    name
  end

-  def self.createDefaultInterventions
+  def self.create_default_interventions
    %w[BreakIntervention QuestionIntervention].each do |name|
      Intervention.find_or_create_by(name: name)
    end
--- a/app/models/proxy_exercise.rb
+++ b/app/models/proxy_exercise.rb
@ -42,7 +42,7 @@ class ProxyExercise < ApplicationRecord
  end

  def get_matching_exercise(user)
-    assigned_user_proxy_exercise = user_proxy_exercise_exercises.where(user: user).first
+    assigned_user_proxy_exercise = user_proxy_exercise_exercises.find_by(user: user)
    if assigned_user_proxy_exercise
      Rails.logger.debug("retrieved assigned exercise for user #{user.id}: Exercise #{assigned_user_proxy_exercise.exercise}")
      assigned_user_proxy_exercise.exercise
@ -105,9 +105,9 @@ exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
      relative_knowledge_improvement[potex] = 0.0
      Rails.logger.debug("review potential exercise #{potex.id}")
      tags.each do |tag|
-        tag_ratio = potex.exercise_tags.where(tag: tag).first.factor.to_f / potex.exercise_tags.inject(0) do |sum, et|
-                                                                              sum += et.factor
-                                                                            end
+        tag_ratio = potex.exercise_tags.find_by(tag: tag).factor.to_f / potex.exercise_tags.inject(0) do |sum, et|
+                                                                          sum + et.factor
+                                                                        end
        max_topic_knowledge_ratio = potex.expected_difficulty * tag_ratio
        old_relative_loss_tag = topic_knowledge_user[tag] / topic_knowledge_max[tag]
        new_relative_loss_tag = topic_knowledge_user[tag] / (topic_knowledge_max[tag] + max_topic_knowledge_ratio)
@ -123,9 +123,9 @@ exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
    @reason[:current_users_knowledge_lack] = current_users_knowledge_lack
    @reason[:relative_knowledge_improvement] = relative_knowledge_improvement

-    Rails.logger.debug('current users knowledge loss: ' + current_users_knowledge_lack.map do |k, v|
-                                                            "#{k} => #{v}"
-                                                          end.to_s)
+    Rails.logger.debug("current users knowledge loss: #{current_users_knowledge_lack.map do |k, v|
+                                                          "#{k} => #{v}"
+                                                        end}")
    Rails.logger.debug("relative improvements #{relative_knowledge_improvement.map {|k, v| "#{k.id}:#{v}" }}")
    best_matching_exercise
  end
@ -166,22 +166,22 @@ exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
  end
  private :scoring_matrix_quantiles

-  def score(user, ex)
-    max_score = ex.maximum_score.to_f
+  def score(user, exercise)
+    max_score = exercise.maximum_score.to_f
    if max_score <= 0
-      Rails.logger.debug("scoring user #{user.id} for exercise #{ex.id}:  score: 0")
+      Rails.logger.debug("scoring user #{user.id} for exercise #{exercise.id}:  score: 0")
      return 0.0
    end
-    points_ratio = ex.maximum_score(user) / max_score
-    if points_ratio == 0.0
-      Rails.logger.debug("scoring user #{user.id} for exercise #{ex.id}: points_ratio=#{points_ratio} score: 0")
+    points_ratio = exercise.maximum_score(user) / max_score
+    if points_ratio.to_d == 0.0.to_d
+      Rails.logger.debug("scoring user #{user.id} for exercise #{exercise.id}: points_ratio=#{points_ratio} score: 0")
      return 0.0
    elsif points_ratio > 1.0
      points_ratio = 1.0 # The score of the exercise was adjusted and is now lower than it was
    end
    points_ratio_index = ((scoring_matrix.size - 1) * points_ratio).to_i
-    working_time_user = ex.accumulated_working_time_for_only(user)
-    quantiles_working_time = ex.get_quantiles(scoring_matrix_quantiles)
+    working_time_user = exercise.accumulated_working_time_for_only(user)
+    quantiles_working_time = exercise.get_quantiles(scoring_matrix_quantiles)
    quantile_index = quantiles_working_time.size
    quantiles_working_time.each_with_index do |quantile_time, i|
      if working_time_user <= quantile_time
@ -190,7 +190,7 @@ exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
      end
    end
    Rails.logger.debug(
-        "scoring user #{user.id} exercise #{ex.id}: worktime #{working_time_user}, points: #{points_ratio}" \
+        "scoring user #{user.id} exercise #{exercise.id}: worktime #{working_time_user}, points: #{points_ratio}" \
        "(index #{points_ratio_index}) quantiles #{quantiles_working_time} placed into quantile index #{quantile_index} " \
        "score: #{scoring_matrix[points_ratio_index][quantile_index]}"
      )
@ -217,12 +217,12 @@ exercise: matching_exercise, proxy_exercise: self, reason: @reason.to_json)
      ex.tags.each do |t|
        tags_counter[t] += 1
        tag_diminishing_return_factor = tag_diminishing_return_function(tags_counter[t], all_used_tags_with_count[t])
-        tag_ratio = ex.exercise_tags.where(tag: t).first.factor.to_f / ex.exercise_tags.inject(0) do |sum, et|
-                                                                         sum + et.factor
-                                                                       end
-        Rails.logger.debug("tag: #{t}, factor: #{ex.exercise_tags.where(tag: t).first.factor}, sumall: #{ex.exercise_tags.inject(0) do |sum, et|
-                                                                                                           sum + et.factor
-                                                                                                         end }")
+        tag_ratio = ex.exercise_tags.find_by(tag: t).factor.to_f / ex.exercise_tags.inject(0) do |sum, et|
+                                                                     sum + et.factor
+                                                                   end
+        Rails.logger.debug("tag: #{t}, factor: #{ex.exercise_tags.find_by(tag: t).factor}, sumall: #{ex.exercise_tags.inject(0) do |sum, et|
+                                                                                                       sum + et.factor
+                                                                                                     end }")
        Rails.logger.debug("tag #{t}, count #{tags_counter[t]}, max: #{all_used_tags_with_count[t]}, factor: #{tag_diminishing_return_factor}")
        Rails.logger.debug("tag_ratio #{tag_ratio}")
        topic_knowledge_ratio = ex.expected_difficulty * tag_ratio
--- a/app/models/submission.rb
+++ b/app/models/submission.rb
@ -127,7 +127,7 @@ class Submission < ApplicationRecord
  end

  def own_unsolved_rfc
-    RequestForComment.unsolved.where(exercise_id: exercise, user_id: user_id).first
+    RequestForComment.unsolved.find_by(exercise_id: exercise, user_id: user_id)
  end

  def unsolved_rfc
--- a/app/models/tag.rb
+++ b/app/models/tag.rb
@ -6,11 +6,7 @@ class Tag < ApplicationRecord

  validates :name, uniqueness: true

-  def destroy
-    if can_be_destroyed?
-      super
-    end
-  end
+  before_destroy :can_be_destroyed?, prepend: true

  def can_be_destroyed?
    exercises.none?
--- a/app/policies/exercise_policy.rb
+++ b/app/policies/exercise_policy.rb
@ -5,7 +5,7 @@ class ExercisePolicy < AdminOrAuthorPolicy
    admin?
  end

-  %i[show? feedback? statistics? get_rfcs_for_exercise?].each do |action|
+  %i[show? feedback? statistics? rfcs_for_exercise?].each do |action|
    define_method(action) { admin? || teacher_in_study_group? || teacher? && @record.public? || author? }
  end

--- a/app/policies/request_for_comment_policy.rb
+++ b/app/policies/request_for_comment_policy.rb
@ -37,11 +37,11 @@ class RequestForCommentPolicy < ApplicationPolicy
    everyone
  end

-  def get_my_comment_requests?
+  def my_comment_requests?
    everyone
  end

-  def get_rfcs_with_my_comments?
+  def rfcs_with_my_comments?
    everyone
  end
 end
--- a/app/services/exercise_service/check_external.rb
+++ b/app/services/exercise_service/check_external.rb
@ -3,6 +3,7 @@
 module ExerciseService
  class CheckExternal < ServiceBase
    def initialize(uuid:, codeharbor_link:)
+      super()
      @uuid = uuid
      @codeharbor_link = codeharbor_link
    end
--- a/app/services/exercise_service/push_external.rb
+++ b/app/services/exercise_service/push_external.rb
@ -3,6 +3,7 @@
 module ExerciseService
  class PushExternal < ServiceBase
    def initialize(zip:, codeharbor_link:)
+      super()
      @zip = zip
      @codeharbor_link = codeharbor_link
    end
--- a/app/services/proforma_service/convert_exercise_to_task.rb
+++ b/app/services/proforma_service/convert_exercise_to_task.rb
@ -7,6 +7,7 @@ module ProformaService
    DEFAULT_LANGUAGE = 'de'

    def initialize(exercise: nil)
+      super()
      @exercise = exercise
    end

--- a/app/services/proforma_service/convert_task_to_exercise.rb
+++ b/app/services/proforma_service/convert_task_to_exercise.rb
@ -3,6 +3,7 @@
 module ProformaService
  class ConvertTaskToExercise < ServiceBase
    def initialize(task:, user:, exercise: nil)
+      super()
      @task = task
      @user = user
      @exercise = exercise || Exercise.new(unpublished: true)
--- a/app/services/proforma_service/export_task.rb
+++ b/app/services/proforma_service/export_task.rb
@ -3,6 +3,7 @@
 module ProformaService
  class ExportTask < ServiceBase
    def initialize(exercise: nil)
+      super()
      @exercise = exercise
    end

--- a/app/services/proforma_service/import.rb
+++ b/app/services/proforma_service/import.rb
@ -3,6 +3,7 @@
 module ProformaService
  class Import < ServiceBase
    def initialize(zip:, user:)
+      super()
      @zip = zip
      @user = user
    end
--- a/app/views/application/_session.html.slim
+++ b/app/views/application/_session.html.slim
@ -6,8 +6,8 @@
      span.caret
    ul.dropdown-menu.p-0.mt-1 role='menu'
      li = link_to(t('request_for_comments.index.all'), request_for_comments_path, class: 'dropdown-item') if policy(:request_for_comment).index?
-      li = link_to(t('request_for_comments.index.get_my_rfc_activity'), my_rfc_activity_path, class: 'dropdown-item')
-      li = link_to(t('request_for_comments.index.get_my_comment_requests'), my_request_for_comments_path, class: 'dropdown-item')
+      li = link_to(t('request_for_comments.index.my_rfc_activity'), my_rfc_activity_path, class: 'dropdown-item')
+      li = link_to(t('request_for_comments.index.my_comment_requests'), my_request_for_comments_path, class: 'dropdown-item')
      - if current_user.try(:admin?) or current_user.try(:teacher?)
        li = link_to(t('consumers.show.link'), current_user.consumer, class: 'dropdown-item') if current_user.consumer and policy(current_user.consumer).show?
        li = link_to(t('internal_users.show.link'), current_user, class: 'dropdown-item') if policy(current_user).show?
--- a/app/views/exercises/index.html.slim
+++ b/app/views/exercises/index.html.slim
@ -45,7 +45,7 @@ h1 = Exercise.model_name.human(count: 2)
              ul.dropdown-menu.float-right role="menu"
                li = link_to(t('shared.show'), exercise, 'data-turbolinks' => "false", class: 'dropdown-item') if policy(exercise).show?
                li = link_to(t('activerecord.models.user_exercise_feedback.other'), feedback_exercise_path(exercise), class: 'dropdown-item') if policy(exercise).feedback?
-                li = link_to(t('activerecord.models.request_for_comment.other'), rfcs_for_exercise_path(exercise), class: 'dropdown-item') if policy(exercise).get_rfcs_for_exercise?
+                li = link_to(t('activerecord.models.request_for_comment.other'), rfcs_for_exercise_path(exercise), class: 'dropdown-item') if policy(exercise).rfcs_for_exercise?
                li = link_to(t('shared.destroy'), exercise, data: {confirm: t('shared.confirm_destroy')}, method: :delete, class: 'dropdown-item') if policy(exercise).destroy?
                li = link_to(t('.clone'), clone_exercise_path(exercise), data: {confirm: t('shared.confirm_destroy')}, method: :post, class: 'dropdown-item') if policy(exercise).clone?
                li = link_to(t('exercises.export_codeharbor.label'), '', class: 'dropdown-item export-start', data: {'exercise-id' => exercise.id}) if policy(exercise).export_external_confirm?
--- a/app/views/exercises/show.html.slim
+++ b/app/views/exercises/show.html.slim
@ -14,7 +14,7 @@ h1
      li = link_to(t('exercises.index.implement'), implement_exercise_path(@exercise), 'data-turbolinks' => "false", class: 'dropdown-item text-dark') if policy(@exercise).implement?
      li = link_to(t('shared.statistics'), statistics_exercise_path(@exercise), 'data-turbolinks' => "false", class: 'dropdown-item text-dark') if policy(@exercise).statistics?
      li = link_to(t('activerecord.models.user_exercise_feedback.other'), feedback_exercise_path(@exercise), class: 'dropdown-item text-dark') if policy(@exercise).feedback?
-      li = link_to(t('activerecord.models.request_for_comment.other'), rfcs_for_exercise_path(@exercise), class: 'dropdown-item text-dark') if policy(@exercise).get_rfcs_for_exercise?
+      li = link_to(t('activerecord.models.request_for_comment.other'), rfcs_for_exercise_path(@exercise), class: 'dropdown-item text-dark') if policy(@exercise).rfcs_for_exercise?
      li = link_to(t('shared.destroy'), @exercise, data: {confirm: t('shared.confirm_destroy')}, method: :delete, class: 'dropdown-item text-dark') if policy(@exercise).destroy?
      li = link_to(t('exercises.index.clone'), clone_exercise_path(@exercise), data: {confirm: t('shared.confirm_destroy')}, method: :post, class: 'dropdown-item text-dark') if policy(@exercise).clone?
      li = link_to(t('exercises.export_codeharbor.label'), '', class: 'dropdown-item export-start text-dark', data: {'exercise-id' => @exercise.id}) if policy(@exercise).export_external_confirm?
--- a/app/views/user_mailer/got_new_comment.slim
+++ b/app/views/user_mailer/got_new_comment.slim
@ -3,5 +3,5 @@
        link_to_comment: link_to(@rfc_link, @rfc_link),
        commenting_user_displayname: @commenting_user_displayname,
        comment_text: @comment_text,
-        link_my_comments: link_to(t('request_for_comments.index.get_my_comment_requests'), my_request_for_comments_url),
+        link_my_comments: link_to(t('request_for_comments.index.my_comment_requests'), my_request_for_comments_url),
        link_all_comments: link_to(t('request_for_comments.index.all'), request_for_comments_url) )
--- a/app/views/user_mailer/got_new_comment_for_subscription.html.slim
+++ b/app/views/user_mailer/got_new_comment_for_subscription.html.slim
@ -3,5 +3,5 @@
        unsubscribe_link: link_to(@unsubscribe_link, @unsubscribe_link),
        author_displayname: @author_displayname,
        comment_text: @comment_text,
-        link_my_comments: link_to(t('request_for_comments.index.get_my_comment_requests'), my_request_for_comments_url),
+        link_my_comments: link_to(t('request_for_comments.index.my_comment_requests'), my_request_for_comments_url),
        link_all_comments: link_to(t('request_for_comments.index.all'), request_for_comments_url) )
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@ -20,7 +20,7 @@ Rails.application.configure do

  # Enable/disable caching. By default caching is disabled.
  # Run rails dev:cache to toggle caching.
-  if Rails.root.join('tmp', 'caching-dev.txt').exist?
+  if Rails.root.join('tmp/caching-dev.txt').exist?
    config.action_controller.perform_caching = true
    config.action_controller.enable_fragment_cache_logging = true

--- a/config/initializers/monkey_patches.rb
+++ b/config/initializers/monkey_patches.rb
@ -3,15 +3,7 @@
 unless Array.respond_to?(:average)
  class Array
    def average
-      inject(:+) / length if present?
-    end
-  end
-end
-
-unless Array.respond_to?(:to_h)
-  class Array
-    def to_h
-      to_h
+      sum / length if present?
    end
  end
 end
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@ -723,11 +723,11 @@ de:
      Mit "Kommentar abschicken" wird der Kommentar dann gesichert und taucht als Sprechblase neben der Zeile auf.
    howto_title: 'Anleitung'
    index:
-      get_my_comment_requests: Meine Kommentaranfragen
+      my_comment_requests: Meine Kommentaranfragen
      all: "Alle Kommentaranfragen"
-      get_rfcs_with_my_comments: Kommentaranfragen die ich kommentiert habe
-      get_my_rfc_activity: "Meine Kommentaraktivität"
-      get_rfcs_for_exercise: "Übungsspezifische Kommentare"
+      rfcs_with_my_comments: Kommentaranfragen die ich kommentiert habe
+      my_rfc_activity: "Meine Kommentaraktivität"
+      rfcs_for_exercise: "Übungsspezifische Kommentare"
      study_groups:
        placeholder: "Lerngruppe"
        current: "Aktuelle Lerngruppe"
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@ -724,10 +724,10 @@ en:
    howto_title: 'How to comment'
    index:
      all: All Requests for Comments
-      get_my_comment_requests: My Requests for Comments
-      get_rfcs_with_my_comments: Requests for Comments I have commented on
-      get_my_rfc_activity: "My Comment Activity"
-      get_rfcs_for_exercise: "Exercise Comments"
+      my_comment_requests: My Requests for Comments
+      rfcs_with_my_comments: Requests for Comments I have commented on
+      my_rfc_activity: "My Comment Activity"
+      rfcs_for_exercise: "Exercise Comments"
      study_groups:
        placeholder: "Study group"
        current: "Current Study Group"
--- a/config/routes.rb
+++ b/config/routes.rb
@ -23,9 +23,9 @@ Rails.application.routes.draw do
    end
  end
  resources :comments, defaults: {format: :json}
-  get '/my_request_for_comments', as: 'my_request_for_comments', to: 'request_for_comments#get_my_comment_requests'
-  get '/my_rfc_activity', as: 'my_rfc_activity', to: 'request_for_comments#get_rfcs_with_my_comments'
-  get '/exercises/:exercise_id/request_for_comments', as: 'rfcs_for_exercise', to: 'request_for_comments#get_rfcs_for_exercise'
+  get '/my_request_for_comments', as: 'my_request_for_comments', to: 'request_for_comments#my_comment_requests'
+  get '/my_rfc_activity', as: 'my_rfc_activity', to: 'request_for_comments#rfcs_with_my_comments'
+  get '/exercises/:exercise_id/request_for_comments', as: 'rfcs_for_exercise', to: 'request_for_comments#rfcs_for_exercise'

  delete '/comment_by_id', to: 'comments#destroy_by_id'
  put '/comments', to: 'comments#update', defaults: {format: :json}
--- a/db/migrate/20150204080832_add_pool_size_to_execution_environments.rb
+++ b/db/migrate/20150204080832_add_pool_size_to_execution_environments.rb
@ -6,7 +6,7 @@ class AddPoolSizeToExecutionEnvironments < ActiveRecord::Migration[4.2]

    reversible do |direction|
      direction.up do
-        ExecutionEnvironment.update_all(pool_size: 0)
+        ExecutionEnvironment.update(pool_size: 0)
      end
    end
  end
--- a/db/migrate/20150317083739_add_memory_limit_to_execution_environments.rb
+++ b/db/migrate/20150317083739_add_memory_limit_to_execution_environments.rb
@ -6,7 +6,7 @@ class AddMemoryLimitToExecutionEnvironments < ActiveRecord::Migration[4.2]

    reversible do |direction|
      direction.up do
-        ExecutionEnvironment.update_all(memory_limit: DockerClient::DEFAULT_MEMORY_LIMIT)
+        ExecutionEnvironment.update(memory_limit: DockerClient::DEFAULT_MEMORY_LIMIT)
      end
    end
  end
--- a/db/migrate/20150317115338_add_network_enabled_to_execution_environments.rb
+++ b/db/migrate/20150317115338_add_network_enabled_to_execution_environments.rb
@ -6,7 +6,7 @@ class AddNetworkEnabledToExecutionEnvironments < ActiveRecord::Migration[4.2]

    reversible do |direction|
      direction.up do
-        ExecutionEnvironment.update_all(network_enabled: true)
+        ExecutionEnvironment.update(network_enabled: true)
      end
    end
  end
--- a/db/migrate/20170205210357_create_interventions.rb
+++ b/db/migrate/20170205210357_create_interventions.rb
@ -17,6 +17,6 @@ class CreateInterventions < ActiveRecord::Migration[4.2]
      t.timestamps
    end

-    Intervention.createDefaultInterventions
+    Intervention.create_default_interventions
  end
 end
--- a/db/migrate/20170403162848_set_default_for_request_for_comment_solved.rb
+++ b/db/migrate/20170403162848_set_default_for_request_for_comment_solved.rb
@ -3,6 +3,6 @@
 class SetDefaultForRequestForCommentSolved < ActiveRecord::Migration[4.2]
  def change
    change_column_default :request_for_comments, :solved, false
-    RequestForComment.where(solved: nil).update_all(solved: false)
+    RequestForComment.where(solved: nil).update(solved: false)
  end
 end
--- a/db/migrate/20170830083601_add_cause_to_testruns.rb
+++ b/db/migrate/20170830083601_add_cause_to_testruns.rb
@ -6,7 +6,7 @@ class AddCauseToTestruns < ActiveRecord::Migration[4.2]
    Testrun.reset_column_information
    Testrun.all.each do |testrun|
      if testrun.submission.nil?
-        say_with_time "#{testrun.id} has no submission" do end
+        say_with_time "#{testrun.id} has no submission"
      else
        testrun.cause = testrun.submission.cause
        testrun.save
--- a/db/migrate/20180130172021_add_reached_full_score_to_request_for_comment.rb
+++ b/db/migrate/20180130172021_add_reached_full_score_to_request_for_comment.rb
@ -4,7 +4,7 @@ class AddReachedFullScoreToRequestForComment < ActiveRecord::Migration[4.2]
  def up
    add_column :request_for_comments, :full_score_reached, :boolean, default: false
    RequestForComment.find_each do |rfc|
-      if rfc.submission.present? && rfc.submission.exercise.has_user_solved(rfc.user)
+      if rfc.submission.present? && rfc.submission.exercise.solved_by?(rfc.user)
        rfc.full_score_reached = true
        rfc.save
      end
--- a/db/migrate/20181119161514_add_user_to_proxy_exercise.rb
+++ b/db/migrate/20181119161514_add_user_to_proxy_exercise.rb
@ -6,6 +6,6 @@ class AddUserToProxyExercise < ActiveRecord::Migration[5.2]
    add_column :proxy_exercises, :public, :boolean, null: false, default: false

    internal_user = InternalUser.find_by(id: 46) || InternalUser.first
-    ProxyExercise.update_all(user_id: internal_user&.id || 1, user_type: internal_user.class.name)
+    ProxyExercise.update(user_id: internal_user&.id || 1, user_type: internal_user.class.name)
  end
 end
--- a/db/migrate/20181126163428_add_user_type_to_remote_evaluation_mappings.rb
+++ b/db/migrate/20181126163428_add_user_type_to_remote_evaluation_mappings.rb
@ -5,6 +5,6 @@ class AddUserTypeToRemoteEvaluationMappings < ActiveRecord::Migration[5.2]
    add_column :remote_evaluation_mappings, :user_type, :string
    # Update all existing records and set user_type to `ExternalUser` (safe way to prevent any function loss).
    # We are not using a default value here on intend to be in line with the other `user_type` columns
-    RemoteEvaluationMapping.update_all(user_type: 'ExternalUser')
+    RemoteEvaluationMapping.update(user_type: 'ExternalUser')
  end
 end
--- a/db/migrate/20181129093207_drop_errors.rb
+++ b/db/migrate/20181129093207_drop_errors.rb
@ -21,7 +21,7 @@ class DropErrors < ActiveRecord::Migration[5.2]
  end

  def change
-    puts 'Migrating CodeOcean::Errors to StructuredErrors using RegEx. This might take a (long) while but will return.'
+    Rails.logger.info 'Migrating CodeOcean::Errors to StructuredErrors using RegEx. This might take a (long) while but will return.'
    submissions_controller = SubmissionsController.new

    # Iterate only over those Errors containing a message and submission_id
--- a/db/migrate/20210512133611_add_service_name_to_active_storage_blobs.active_storage.rb
+++ b/db/migrate/20210512133611_add_service_name_to_active_storage_blobs.active_storage.rb
@ -6,8 +6,8 @@ class AddServiceNameToActiveStorageBlobs < ActiveRecord::Migration[6.0]
    if table_exists?(:active_storage_blobs) && !column_exists?(:active_storage_blobs, :service_name)
      add_column :active_storage_blobs, :service_name, :string

-      if configured_service = ActiveStorage::Blob.service.name
-        ActiveStorage::Blob.unscoped.update_all(service_name: configured_service)
+      if (configured_service = ActiveStorage::Blob.service.name)
+        ActiveStorage::Blob.unscoped.update(service_name: configured_service)
      end

      change_column :active_storage_blobs, :service_name, :string, null: false
--- a/db/seeds.rb
+++ b/db/seeds.rb
@ -23,7 +23,7 @@ Rails.application.eager_load!
 (ApplicationRecord.descendants - [ActiveRecord::SchemaMigration, User]).each(&:delete_all)

 # delete file uploads
-FileUtils.rm_rf(Rails.root.join('public', 'uploads'))
+FileUtils.rm_rf(Rails.root.join('public/uploads'))

 # load environment-dependent seeds
-load(Rails.root.join('db', 'seeds', "#{Rails.env}.rb"))
+load(Rails.root.join("db/seeds/#{Rails.env}.rb"))
--- a/db/seeds/fibonacci/exercise.rb
+++ b/db/seeds/fibonacci/exercise.rb
@ -1,3 +1,3 @@
 # frozen_string_literal: true

-def fibonacci(n); end
+def fibonacci(number); end
--- a/db/seeds/fibonacci/exercise_spec_3.rb
+++ b/db/seeds/fibonacci/exercise_spec_3.rb
@ -4,11 +4,11 @@ require './exercise'
 require './reference'

 describe '#fibonacci' do
-  SAMPLE_COUNT = 32
+  let(:sample_count) { 32 }

  let(:reference) { Class.new.extend(Reference) }

-  SAMPLE_COUNT.times do |i|
+  sample_count.times do |i|
    instance_eval do
      it "obtains the correct result for input #{i}" do
        expect(fibonacci(i)).to eq(reference.fibonacci(i))
--- a/db/seeds/fibonacci/reference.rb
+++ b/db/seeds/fibonacci/reference.rb
@ -1,7 +1,7 @@
 # frozen_string_literal: true

 module Reference
-  def fibonacci(n)
-    n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2)
+  def fibonacci(number)
+    number < 2 ? number : fibonacci(number - 1) + fibonacci(number - 2)
  end
 end
--- a/db/seeds/hello_world/exercise.rb
+++ b/db/seeds/hello_world/exercise.rb
@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+# Write your code here
--- a/db/seeds/production.rb
+++ b/db/seeds/production.rb
@ -29,7 +29,7 @@ FileType.create_factories

 # change all resources' author
 [ExecutionEnvironment, Exercise, FileType].each do |model|
-  model.update_all(user_id: InternalUser.first.id)
+  model.update(user_id: InternalUser.first.id)
 end

 # delete temporary users
--- a/db/seeds/sql_select/comparator.rb
+++ b/db/seeds/sql_select/comparator.rb
@ -10,5 +10,7 @@ database = SQLite3::Database.new('/database.db')
 missing_tuples = database.execute(REFERENCE_QUERY) - database.execute(STUDENT_QUERY)
 unexpected_tuples = database.execute(STUDENT_QUERY) - database.execute(REFERENCE_QUERY)

+# rubocop:disable Rails/Output
 puts("Missing tuples: #{missing_tuples}")
 puts("Unexpected tuples: #{unexpected_tuples}")
+# rubocop:enable Rails/Output
--- a/db/seeds/tdd/exercise.rb
+++ b/db/seeds/tdd/exercise.rb
@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+# Write your code here
--- a/lib/active_model/validations/boolean_presence_validator.rb
+++ b/lib/active_model/validations/boolean_presence_validator.rb
@ -3,10 +3,12 @@
 module ActiveModel
  module Validations
    class BooleanPresenceValidator < EachValidator
+      BOOLEAN_VALUES = [false, true].freeze
+
      def validate(record)
        [attributes].flatten.each do |attribute|
          value = record.send(:read_attribute_for_validation, attribute)
-          record.errors.add(attribute, nil, options) unless [false, true].include?(value)
+          record.errors.add(attribute, nil, options) unless BOOLEAN_VALUES.include?(value)
        end
      end
    end
--- a/lib/assessor.rb
+++ b/lib/assessor.rb
@ -12,7 +12,7 @@ class Assessor

  def calculate_score(test_outcome)
    score = 0.0
-    if test_outcome[:passed].to_f != 0.0 && test_outcome[:count].to_f != 0.0
+    if test_outcome[:passed].to_d != 0.0.to_d && test_outcome[:count].to_d != 0.0.to_d
      score = (test_outcome[:passed].to_f / test_outcome[:count])
      # prevent negative scores
      score = [0.0, score].max
--- a/lib/code_ocean/config.rb
+++ b/lib/code_ocean/config.rb
@ -9,7 +9,7 @@ module CodeOcean
    def read(options = {})
      path = Rails.root.join('config', "#{@filename}.yml#{options[:erb] ? '.erb' : ''}")
      if ::File.exist?(path)
-        content = options[:erb] ? YAML.safe_load(ERB.new(::File.new(path, 'r').read).result) : YAML.load_file(path)
+        content = options[:erb] ? YAML.safe_load(ERB.new(::File.new(path, 'r').read).result, aliases: true, permitted_classes: [Range]) : YAML.load_file(path)
        content[Rails.env].with_indifferent_access
      else
        raise Error.new("Configuration file not found: #{path}")
--- a/lib/docker_client.rb
+++ b/lib/docker_client.rb
@ -78,7 +78,7 @@ class DockerClient
    }
  end

-  def create_socket(container, stderr = false)
+  def create_socket(container, stderr: false)
    # TODO: factor out query params
    # todo separate stderr
    query_params = "logs=0&stream=1&#{stderr ? 'stderr=1' : 'stdout=1&stdin=1'}"
@ -111,7 +111,7 @@ class DockerClient
  end

  def self.create_container(execution_environment)
-    tries ||= 0
+    # tries ||= 0
    # container.start sometimes creates the passed local_workspace_path on disk (depending on the setup).
    # this is however not guaranteed and caused issues on the server already. Therefore create the necessary folders manually!
    local_workspace_path = generate_local_workspace_path
@ -133,14 +133,14 @@ class DockerClient
        Thread.new do
          timeout = SELF_DESTROY_GRACE_PERIOD.to_i
          sleep(timeout)
-          container.docker_client.kill_container(container, false)
+          container.docker_client.kill_container(container)
          Rails.logger.info("Force killing container in status #{container.status} after #{Time.zone.now - container.start_time} seconds.")
        ensure
          # guarantee that the thread is releasing the DB connection after it is done
          ActiveRecord::Base.connection_pool.release_connection
        end
      else
-        container.docker_client.kill_container(container, false)
+        container.docker_client.kill_container(container)
        Rails.logger.info("Killing container in status #{container.status} after #{Time.zone.now - container.start_time} seconds.")
      end
    ensure
@ -280,7 +280,7 @@ class DockerClient
      {status: :container_depleted, waiting_for_container_time: waiting_for_container_time,
 container_execution_time: nil}
    end
-  rescue Excon::Errors::SocketError => e
+  rescue Excon::Errors::SocketError
    # socket errors seems to be normal when using exec
    # so lets ignore them for now
    # (tries += 1) <= RETRY_COUNT ? retry : raise(error)
@ -310,10 +310,8 @@ container_execution_time: nil}
  end

  def kill_after_timeout(container)
-    "
-    We need to start a second thread to kill the websocket connection,
-    as it is impossible to determine whether further input is requested.
-    "
+    # We need to start a second thread to kill the websocket connection,
+    # as it is impossible to determine whether further input is requested.
    container.status = :executing
    @thread = Thread.new do
      timeout = @execution_environment.permitted_execution_time.to_i # seconds
@ -365,16 +363,14 @@ container_execution_time: nil}
    end
  end

-  def kill_container(container, _create_new = true)
+  def kill_container(container)
    exit_thread_if_alive
    Rails.logger.info("killing container #{container}")
    self.class.destroy_container(container)
  end

  def execute_run_command(submission, filename, &block)
-    "
-    Run commands by attaching a websocket to Docker.
-    "
+    # Run commands by attaching a websocket to Docker.
    filepath = submission.collect_files.find {|f| f.name_with_extension == filename }.filepath
    command = submission.execution_environment.run_command % command_substitutions(filepath)
    create_workspace_files = proc { create_workspace_files(container, submission) }
@ -383,9 +379,7 @@ container_execution_time: nil}
  end

  def execute_test_command(submission, filename, &block)
-    "
-    Stick to existing Docker API with exec command.
-    "
+    # Stick to existing Docker API with exec command.
    file = submission.collect_files.find {|f| f.name_with_extension == filename }
    filepath = file.filepath
    command = submission.execution_environment.test_command % command_substitutions(filepath)
@ -495,26 +489,23 @@ container_execution_time: nil}
    if output.nil?
      kill_container(container)
    else
-      result = {status: (output[2]).zero? ? :ok : :failed, stdout: output[0].join.force_encoding('utf-8'),
-stderr: output[1].join.force_encoding('utf-8')}
+      result = {status: (output[2])&.zero? ? :ok : :failed, stdout: output[0].join.force_encoding('utf-8'), stderr: output[1].join.force_encoding('utf-8')}
    end

    # if we use pooling and recylce the containers, put it back. otherwise, destroy it.
    if DockerContainerPool.config[:active] && RECYCLE_CONTAINERS
-      self.class.return_container(container,
-        @execution_environment)
+      self.class.return_container(container, @execution_environment)
    else
      self.class.destroy_container(container)
    end
    result
  rescue Timeout::Error
    Rails.logger.info("got timeout error for container #{container}")
-    stdout = container.exec(['cat', '/tmp/stdout.log'])[0].join.force_encoding('utf-8')
-    stderr = container.exec(['cat', '/tmp/stderr.log'])[0].join.force_encoding('utf-8')
+    stdout = container.exec(%w[cat /tmp/stdout.log])[0].join.force_encoding('utf-8')
+    stderr = container.exec(%w[cat /tmp/stderr.log])[0].join.force_encoding('utf-8')
    kill_container(container)
    {status: :timeout, stdout: stdout, stderr: stderr}
  end
-
  private :send_command

  class Error < RuntimeError; end
--- a/lib/file_tree.rb
+++ b/lib/file_tree.rb
@ -52,9 +52,7 @@ class FileTree < Tree::TreeNode
  private :map_to_js_tree

  def node_icon(node)
-    if node.is_root?
-      folder_icon
-    elsif node.is_leaf?
+    if node.is_leaf? && !node.is_root?
      file_icon(node.content)
    else
      folder_icon
--- a/lib/python20_course_week.rb
+++ b/lib/python20_course_week.rb
@ -9,13 +9,9 @@ class Python20CourseWeek
        2
      when /Python20 Aufgabe 3/
        3
-      when /Python20 Aufgabe 4/
+      when /Python20 Aufgabe 4/, /Python20 Snake/
        4
-      when /Python20 Snake/
-        4
-      else
-        # Not part of the Python20 course
-        nil
+      # else: Not part of the Python20 course
    end
  end

--- a/lib/tasks/detect_exercise_anomalies.rake
+++ b/lib/tasks/detect_exercise_anomalies.rake
@ -81,7 +81,7 @@ namespace :detect_exercise_anomalies do
  def find_anomalies(collection)
    working_times = collect_working_times(collection).compact
    if working_times.values.size.positive?
-      average = working_times.values.reduce(:+) / working_times.values.size
+      average = working_times.values.sum / working_times.values.size
      return working_times.select do |_, working_time|
        working_time > average * MAX_TIME_FACTOR or working_time < average * MIN_TIME_FACTOR
      end
@ -120,7 +120,8 @@ namespace :detect_exercise_anomalies do
      users_to_notify = []

      users = {}
-      %i[performers_by_time performers_by_score].each do |method|
+      methods = %i[performers_by_time performers_by_score]
+      methods.each do |method|
        # merge users found by multiple methods returning a hash {best: [], worst: []}
        users = users.merge(send(method, exercise, NUMBER_OF_USERS_PER_CLASS)) {|_key, this, other| this + other }
      end
--- a/spec/concerns/lti_spec.rb
+++ b/spec/concerns/lti_spec.rb
@ -33,11 +33,11 @@ describe Lti do
    let(:last_name) { 'Doe' }
    let(:full_name) { 'John Doe' }
    let(:provider) { double }
-    let(:provider_full) { double(lis_person_name_full: full_name) }
+    let(:provider_full) { instance_double('IMS::LTI::ToolProvider', lis_person_name_full: full_name) }

    context 'when a full name is provided' do
      it 'returns the full name' do
-        expect(provider_full).to receive(:lis_person_name_full).twice.and_return(full_name)
+        allow(provider_full).to receive(:lis_person_name_full).and_return(full_name)
        expect(controller.send(:external_user_name, provider_full)).to eq(full_name)
      end
    end
@ -45,7 +45,7 @@ describe Lti do
    context 'when only partial information is provided' do
      it 'returns the first available name' do
        expect(provider).to receive(:lis_person_name_full)
-        expect(provider).to receive(:lis_person_name_given).and_return(first_name)
+        allow(provider).to receive(:lis_person_name_given).and_return(first_name)
        expect(provider).not_to receive(:lis_person_name_family)
        expect(controller.send(:external_user_name, provider)).to eq(first_name)
      end
@ -64,7 +64,7 @@ describe Lti do
    context 'with a return URL' do
      let(:consumer_return_url) { 'http://example.org' }

-      before { expect(controller).to receive(:params).and_return(launch_presentation_return_url: consumer_return_url) }
+      before { allow(controller).to receive(:params).and_return(launch_presentation_return_url: consumer_return_url) }

      it 'redirects to the tool consumer' do
        expect(controller).to receive(:redirect_to).with(consumer_return_url)
@ -80,8 +80,8 @@ describe Lti do

    context 'without a return URL' do
      before do
-        expect(controller).to receive(:params).and_return({})
-        expect(controller).to receive(:redirect_to).with(:root)
+        allow(controller).to receive(:params).and_return({})
+        allow(controller).to receive(:redirect_to).with(:root)
      end

      it 'redirects to the root URL' do
@ -104,7 +104,10 @@ describe Lti do
    let(:consumer) { FactoryBot.create(:consumer) }
    let(:score) { 0.5 }
    let(:submission) { FactoryBot.create(:submission) }
-    let!(:lti_parameter) { FactoryBot.create(:lti_parameter, consumers_id: consumer.id, external_users_id: submission.user_id, exercises_id: submission.exercise_id) }
+
+    before do
+      FactoryBot.create(:lti_parameter, consumers_id: consumer.id, external_users_id: submission.user_id, exercises_id: submission.exercise_id)
+    end

    context 'with an invalid score' do
      it 'raises an exception' do
@ -117,7 +120,7 @@ describe Lti do
      context 'with a tool consumer' do
        context 'when grading is not supported' do
          it 'returns a corresponding status' do
-            expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:outcome_service?).and_return(false)
+            allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:outcome_service?).and_return(false)
            allow(submission).to receive(:normalized_score).and_return score
            expect(controller.send(:send_score, submission)[:status]).to eq('unsupported')
          end
@ -127,12 +130,12 @@ describe Lti do
          let(:response) { double }

          before do
-            expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:outcome_service?).and_return(true)
-            expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:post_replace_result!).with(score).and_return(response)
-            expect(response).to receive(:response_code).at_least(:once).and_return(200)
-            expect(response).to receive(:post_response).and_return(response)
-            expect(response).to receive(:body).at_least(:once).and_return('')
-            expect(response).to receive(:code_major).at_least(:once).and_return('success')
+            allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:outcome_service?).and_return(true)
+            allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:post_replace_result!).with(score).and_return(response)
+            allow(response).to receive(:response_code).at_least(:once).and_return(200)
+            allow(response).to receive(:post_response).and_return(response)
+            allow(response).to receive(:body).at_least(:once).and_return('')
+            allow(response).to receive(:code_major).at_least(:once).and_return('success')
          end

          it 'sends the score' do
--- a/spec/concerns/submission_scoring_spec.rb
+++ b/spec/concerns/submission_scoring_spec.rb
@ -8,30 +8,29 @@ end

 describe SubmissionScoring do
  let(:controller) { Controller.new }
-
-  before(:all) { @submission = FactoryBot.create(:submission, cause: 'submit') }
+  let(:submission) { FactoryBot.create(:submission, cause: 'submit') }

  before { controller.instance_variable_set(:@current_user, FactoryBot.create(:external_user)) }

  describe '#collect_test_results' do
-    after { controller.send(:collect_test_results, @submission) }
+    after { controller.send(:collect_test_results, submission) }

    it 'executes every teacher-defined test file' do
-      @submission.collect_files.select(&:teacher_defined_assessment?).each do |file|
-        expect(controller).to receive(:execute_test_file).with(file, @submission).and_return({})
+      submission.collect_files.select(&:teacher_defined_assessment?).each do |file|
+        allow(controller).to receive(:execute_test_file).with(file, submission).and_return({})
      end
    end
  end

  describe '#score_submission' do
-    after { controller.score_submission(@submission) }
+    after { controller.score_submission(submission) }

    it 'collects the test results' do
-      expect(controller).to receive(:collect_test_results).and_return([])
+      allow(controller).to receive(:collect_test_results).and_return([])
    end

    it 'assigns a score to the submissions' do
-      expect(@submission).to receive(:update).with(score: anything)
+      expect(submission).to receive(:update).with(score: anything)
    end
  end
 end
--- a/spec/controllers/application_controller_spec.rb
+++ b/spec/controllers/application_controller_spec.rb
@ -27,7 +27,7 @@ describe ApplicationController do

  describe '#render_not_authorized' do
    before do
-      expect(controller).to receive(:welcome) { controller.send(:render_not_authorized) }
+      allow(controller).to receive(:welcome) { controller.send(:render_not_authorized) }
      get :welcome
    end

@ -41,14 +41,14 @@ describe ApplicationController do
    context 'when specifying a locale' do
      before { allow(session).to receive(:[]=).at_least(:once) }

-      context "using the 'custom_locale' parameter" do
+      context "when using the 'custom_locale' parameter" do
        it 'overwrites the session' do
          expect(session).to receive(:[]=).with(:locale, locale.to_s)
          get :welcome, params: {custom_locale: locale}
        end
      end

-      context "using the 'locale' parameter" do
+      context "when using the 'locale' parameter" do
        it 'overwrites the session' do
          expect(session).to receive(:[]=).with(:locale, locale.to_s)
          get :welcome, params: {locale: locale}
--- a/spec/controllers/codeharbor_links_controller_spec.rb
+++ b/spec/controllers/codeharbor_links_controller_spec.rb
@ -14,7 +14,7 @@ describe CodeharborLinksController do
    allow(controller).to receive(:current_user).and_return(user)
  end

-  context 'GET #new' do
+  describe 'GET #new' do
    before do
      get :new
    end
--- a/spec/controllers/consumers_controller_spec.rb
+++ b/spec/controllers/consumers_controller_spec.rb
@ -54,9 +54,10 @@ describe ConsumersController do
  end

  describe 'GET #index' do
-    let!(:consumers) { FactoryBot.create_pair(:consumer) }
-
-    before { get :index }
+    before do
+      FactoryBot.create_pair(:consumer)
+      get :index
+    end

    expect_assigns(consumers: Consumer.all)
    expect_status(200)
--- a/spec/controllers/execution_environments_controller_spec.rb
+++ b/spec/controllers/execution_environments_controller_spec.rb
@ -9,7 +9,7 @@ describe ExecutionEnvironmentsController do
  before { allow(controller).to receive(:current_user).and_return(user) }

  describe 'POST #create' do
-    before { expect(DockerClient).to receive(:image_tags).at_least(:once).and_return([]) }
+    before { allow(DockerClient).to receive(:image_tags).at_least(:once).and_return([]) }

    context 'with a valid execution environment' do
      let(:perform_request) { proc { post :create, params: {execution_environment: FactoryBot.build(:ruby).attributes} } }
@ -50,7 +50,7 @@ describe ExecutionEnvironmentsController do

  describe 'GET #edit' do
    before do
-      expect(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
+      allow(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
      get :edit, params: {id: execution_environment.id}
    end

@ -64,8 +64,8 @@ describe ExecutionEnvironmentsController do
    let(:command) { 'which ruby' }

    before do
-      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)
+      allow(DockerClient).to receive(:new).with(execution_environment: execution_environment).and_call_original
+      allow_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).with(command)
      post :execute_command, params: {command: command, id: execution_environment.id}
    end

@ -76,9 +76,10 @@ describe ExecutionEnvironmentsController do
  end

  describe 'GET #index' do
-    before(:all) { FactoryBot.create_pair(:ruby) }
-
-    before { get :index }
+    before do
+      FactoryBot.create_pair(:ruby)
+      get :index
+    end

    expect_assigns(execution_environments: ExecutionEnvironment.all)
    expect_status(200)
@ -87,7 +88,7 @@ describe ExecutionEnvironmentsController do

  describe 'GET #new' do
    before do
-      expect(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
+      allow(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
      get :new
    end

@ -102,8 +103,8 @@ describe ExecutionEnvironmentsController do
      let(:docker_images) { [1, 2, 3] }

      before do
-        expect(DockerClient).to receive(:check_availability!).at_least(:once)
-        expect(DockerClient).to receive(:image_tags).and_return(docker_images)
+        allow(DockerClient).to receive(:check_availability!).at_least(:once)
+        allow(DockerClient).to receive(:image_tags).and_return(docker_images)
        controller.send(:set_docker_images)
      end

@ -114,7 +115,7 @@ describe ExecutionEnvironmentsController do
      let(:error_message) { 'Docker is unavailable' }

      before do
-        expect(DockerClient).to receive(:check_availability!).at_least(:once).and_raise(DockerClient::Error.new(error_message))
+        allow(DockerClient).to receive(:check_availability!).at_least(:once).and_raise(DockerClient::Error.new(error_message))
        controller.send(:set_docker_images)
      end

@ -154,7 +155,7 @@ describe ExecutionEnvironmentsController do
  describe 'PUT #update' do
    context 'with a valid execution environment' do
      before do
-        expect(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
+        allow(DockerClient).to receive(:image_tags).at_least(:once).and_return([])
        put :update, params: {execution_environment: FactoryBot.attributes_for(:ruby), id: execution_environment.id}
      end

--- a/spec/controllers/exercises_controller_spec.rb
+++ b/spec/controllers/exercises_controller_spec.rb
@ -45,7 +45,7 @@ describe ExercisesController do

    context 'when saving fails' do
      before do
-        expect_any_instance_of(Exercise).to receive(:save).and_return(false)
+        allow_any_instance_of(Exercise).to receive(:save).and_return(false)
        perform_request.call
      end

@ -87,7 +87,7 @@ describe ExercisesController do
        let(:files_attributes) { {'0' => FactoryBot.build(:file, file_type: file_type).attributes.merge(content: uploaded_file)} }

        context 'when uploading a binary file' do
-          let(:file_path) { Rails.root.join('db', 'seeds', 'audio_video', 'devstories.mp4') }
+          let(:file_path) { Rails.root.join('db/seeds/audio_video/devstories.mp4') }
          let(:file_type) { FactoryBot.create(:dot_mp4) }
          let(:uploaded_file) { Rack::Test::UploadedFile.new(file_path, 'video/mp4', true) }

@ -102,7 +102,7 @@ describe ExercisesController do
        end

        context 'when uploading a non-binary file' do
-          let(:file_path) { Rails.root.join('db', 'seeds', 'fibonacci', 'exercise.rb') }
+          let(:file_path) { Rails.root.join('db/seeds/fibonacci/exercise.rb') }
          let(:file_type) { FactoryBot.create(:dot_rb) }
          let(:uploaded_file) { Rack::Test::UploadedFile.new(file_path, 'text/x-ruby', false) }

@ -189,9 +189,10 @@ describe ExercisesController do
  describe 'GET #index' do
    let(:scope) { Pundit.policy_scope!(user, Exercise) }

-    before(:all) { FactoryBot.create_pair(:dummy) }
-
-    before { get :index }
+    before do
+      FactoryBot.create_pair(:dummy)
+      get :index
+    end

    expect_assigns(exercises: :scope)
    expect_status(200)
@ -208,7 +209,7 @@ describe ExercisesController do
  end

  describe 'GET #show' do
-    context 'as admin' do
+    context 'when being admin' do
      before { get :show, params: {id: exercise.id} }

      expect_assigns(exercise: :exercise)
@ -218,7 +219,7 @@ describe ExercisesController do
  end

  describe 'GET #reload' do
-    context 'as anyone' do
+    context 'when being anyone' do
      before { get :reload, format: :json, params: {id: exercise.id} }

      expect_assigns(exercise: :exercise)
@ -239,22 +240,22 @@ describe ExercisesController do
    let(:output) { {} }
    let(:perform_request) { post :submit, format: :json, params: {id: exercise.id, submission: {cause: 'submit', exercise_id: exercise.id}} }
    let(:user) { FactoryBot.create(:external_user) }
-    let!(:lti_parameter) { FactoryBot.create(:lti_parameter, external_user: user, exercise: exercise) }

    before do
+      FactoryBot.create(:lti_parameter, external_user: user, exercise: exercise)
      allow_any_instance_of(Submission).to receive(:normalized_score).and_return(1)
-      expect(controller).to receive(:collect_test_results).and_return([{score: 1, weight: 1}])
-      expect(controller).to receive(:score_submission).and_call_original
+      allow(controller).to receive(:collect_test_results).and_return([{score: 1, weight: 1}])
+      allow(controller).to receive(:score_submission).and_call_original
    end

    context 'when LTI outcomes are supported' do
      before do
-        expect(controller).to receive(:lti_outcome_service?).and_return(true)
+        allow(controller).to receive(:lti_outcome_service?).and_return(true)
      end

      context 'when the score transmission succeeds' do
        before do
-          expect(controller).to receive(:send_score).and_return(status: 'success')
+          allow(controller).to receive(:send_score).and_return(status: 'success')
          perform_request
        end

@ -270,7 +271,7 @@ describe ExercisesController do

      context 'when the score transmission fails' do
        before do
-          expect(controller).to receive(:send_score).and_return(status: 'unsupported')
+          allow(controller).to receive(:send_score).and_return(status: 'unsupported')
          perform_request
        end

@ -287,8 +288,7 @@ describe ExercisesController do

    context 'when LTI outcomes are not supported' do
      before do
-        expect(controller).to receive(:lti_outcome_service?).and_return(false)
-        expect(controller).not_to receive(:send_score)
+        allow(controller).to receive(:lti_outcome_service?).and_return(false)
        perform_request
      end

@ -298,6 +298,10 @@ describe ExercisesController do
        expect(assigns(:submission)).to be_a(Submission)
      end

+      it 'does not send scores' do
+        expect(controller).not_to receive(:send_score)
+      end
+
      expect_json
      expect_status(200)
    end
@ -333,7 +337,7 @@ describe ExercisesController do
    let(:external_check_hash) { {message: message, exercise_found: true, update_right: update_right, error: error} }
    let(:message) { 'message' }
    let(:update_right) { true }
-    let(:error) {}
+    let(:error) { nil }

    before { allow(ExerciseService::CheckExternal).to receive(:call).with(uuid: exercise.uuid, codeharbor_link: codeharbor_link).and_return(external_check_hash) }

@ -384,7 +388,7 @@ describe ExercisesController do

    let!(:codeharbor_link) { FactoryBot.create(:codeharbor_link, user: user) }
    let(:post_request) { post :export_external_confirm, params: {id: exercise.id, codeharbor_link: codeharbor_link.id} }
-    let(:error) {}
+    let(:error) { nil }
    let(:zip) { 'zip' }

    before do
--- a/spec/controllers/file_types_controller_spec.rb
+++ b/spec/controllers/file_types_controller_spec.rb
@ -57,9 +57,10 @@ describe FileTypesController do
  end

  describe 'GET #index' do
-    before(:all) { FactoryBot.create_pair(:dot_rb) }
-
-    before { get :index }
+    before do
+      FactoryBot.create_pair(:dot_rb)
+      get :index
+    end

    expect_assigns(file_types: FileType.all)
    expect_status(200)
--- a/spec/controllers/internal_users_controller_spec.rb
+++ b/spec/controllers/internal_users_controller_spec.rb
@ -45,6 +45,9 @@ describe InternalUsersController do
    before do
      user.send(:setup_activation)
      user.save(validate: false)
+    end
+
+    it 'adds an activation token' do
      expect(user.activation_token).to be_present
    end

@ -171,7 +174,7 @@ describe InternalUsersController do
      before do
        allow(controller).to receive(:set_sentry_context).and_return(nil)

-        expect(controller).to receive(:current_user).and_return(nil)
+        allow(controller).to receive(:current_user).and_return(nil)
        get :forgot_password
      end

@ -183,7 +186,7 @@ describe InternalUsersController do
      before do
        allow(controller).to receive(:set_sentry_context).and_return(nil)

-        expect(controller).to receive(:current_user).and_return(user)
+        allow(controller).to receive(:current_user).and_return(user)
        get :forgot_password
      end

@ -199,7 +202,7 @@ describe InternalUsersController do
      before { perform_request.call }

      it 'delivers instructions to reset the password' do
-        expect(InternalUser).to receive(:where).and_return([user])
+        allow(InternalUser).to receive(:where).and_return([user])
        expect(user).to receive(:deliver_reset_password_instructions!)
        perform_request.call
      end
--- a/spec/controllers/request_for_comments_controller_spec.rb
+++ b/spec/controllers/request_for_comments_controller_spec.rb
@ -32,24 +32,24 @@ describe RequestForCommentsController do
    end
  end

-  describe 'GET #get_my_comment_requests' do
-    before { get :get_my_comment_requests }
+  describe 'GET #my_comment_requests' do
+    before { get :my_comment_requests }

    expect_status(200)
    expect_template(:index)
  end

-  describe 'GET #get_rfcs_with_my_comments' do
-    before { get :get_rfcs_with_my_comments }
+  describe 'GET #rfcs_with_my_comments' do
+    before { get :rfcs_with_my_comments }

    expect_status(200)
    expect_template(:index)
  end

-  describe 'GET #get_rfcs_for_exercise' do
+  describe 'GET #rfcs_for_exercise' do
    before do
      exercise = FactoryBot.create(:even_odd)
-      get :get_rfcs_for_exercise, params: {exercise_id: exercise.id}
+      get :rfcs_for_exercise, params: {exercise_id: exercise.id}
    end

    expect_status(200)
--- a/spec/controllers/sessions_controller_spec.rb
+++ b/spec/controllers/sessions_controller_spec.rb
@ -58,8 +58,8 @@ describe SessionsController do

    context 'without a unique OAuth nonce' do
      it 'refuses the LTI launch' do
-        expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true)
-        expect(NonceStore).to receive(:has?).with(nonce).and_return(true)
+        allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true)
+        allow(NonceStore).to receive(:has?).with(nonce).and_return(true)
        expect(controller).to receive(:refuse_lti_launch).with(message: I18n.t('sessions.oauth.used_nonce')).and_call_original
        post :create_through_lti, params: {oauth_consumer_key: consumer.oauth_key, oauth_nonce: nonce, oauth_signature: SecureRandom.hex}
      end
@ -67,7 +67,7 @@ describe SessionsController do

    context 'without a valid exercise token' do
      it 'refuses the LTI launch' do
-        expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true)
+        allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true)
        expect(controller).to receive(:refuse_lti_launch).with(message: I18n.t('sessions.oauth.invalid_exercise_token')).and_call_original
        post :create_through_lti, params: {custom_token: '', oauth_consumer_key: consumer.oauth_key, oauth_nonce: nonce, oauth_signature: SecureRandom.hex, user_id: '123'}
      end
@ -78,7 +78,7 @@ describe SessionsController do
      let(:perform_request) { post :create_through_lti, params: {custom_locale: locale, custom_token: exercise.token, oauth_consumer_key: consumer.oauth_key, oauth_nonce: nonce, oauth_signature: SecureRandom.hex, user_id: user.external_id} }
      let(:user) { FactoryBot.create(:external_user, consumer_id: consumer.id) }

-      before { expect_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true) }
+      before { allow_any_instance_of(IMS::LTI::ToolProvider).to receive(:valid_request?).and_return(true) }

      it 'assigns the current user' do
        perform_request
@ -112,7 +112,7 @@ describe SessionsController do
        let(:message) { I18n.t('sessions.create_through_lti.session_with_outcome', consumer: consumer) }

        before do
-          expect(controller).to receive(:lti_outcome_service?).and_return(true)
+          allow(controller).to receive(:lti_outcome_service?).and_return(true)
          perform_request
        end

@ -123,7 +123,7 @@ describe SessionsController do
        let(:message) { I18n.t('sessions.create_through_lti.session_without_outcome', consumer: consumer) }

        before do
-          expect(controller).to receive(:lti_outcome_service?).and_return(false)
+          allow(controller).to receive(:lti_outcome_service?).and_return(false)
          perform_request
        end

@ -159,7 +159,7 @@ describe SessionsController do

    before do
      allow(controller).to receive(:set_sentry_context).and_return(nil)
-      expect(controller).to receive(:current_user).at_least(:once).and_return(user)
+      allow(controller).to receive(:current_user).at_least(:once).and_return(user)
    end

    context 'with an internal user' do
@ -199,7 +199,14 @@ describe SessionsController do

  describe 'GET #destroy_through_lti' do
    let(:perform_request) { proc { get :destroy_through_lti, params: {consumer_id: consumer.id, submission_id: submission.id} } }
-    let(:submission) { FactoryBot.create(:submission, exercise: FactoryBot.create(:dummy)) }    before { perform_request.call }
+    let(:submission) { FactoryBot.create(:submission, exercise: FactoryBot.create(:dummy)) }
+
+    before do
+      # Todo replace session with lti_parameter
+      # Todo create LtiParameter Object
+      # session[:lti_parameters] = {}
+      perform_request.call
+    end

    it 'clears the session' do
      # Todo replace session with lti_parameter /should be done already
@ -216,7 +223,7 @@ describe SessionsController do
      before do
        allow(controller).to receive(:set_sentry_context).and_return(nil)

-        expect(controller).to receive(:current_user).and_return(nil)
+        allow(controller).to receive(:current_user).and_return(nil)
        get :new
      end

@ -228,7 +235,7 @@ describe SessionsController do
      before do
        allow(controller).to receive(:set_sentry_context).and_return(nil)

-        expect(controller).to receive(:current_user).and_return(FactoryBot.build(:teacher))
+        allow(controller).to receive(:current_user).and_return(FactoryBot.build(:teacher))
        get :new
      end

--- a/spec/controllers/submissions_controller_spec.rb
+++ b/spec/controllers/submissions_controller_spec.rb
@ -50,7 +50,7 @@ describe SubmissionsController do

      before { get :download_file, params: {filename: file.name_with_extension, id: submission.id} }

-      context 'for a binary file' do
+      context 'with a binary file' do
        let(:file) { submission.collect_files.detect {|file| file.name == 'exercise' && file.file_type.file_extension == '.sql' } }

        expect_assigns(file: :file)
@ -69,7 +69,7 @@ describe SubmissionsController do

      before { get :download_file, params: {filename: file.name_with_extension, id: submission.id} }

-      context 'for a binary file' do
+      context 'with a binary file' do
        let(:file) { submission.collect_files.detect {|file| file.file_type.file_extension == '.mp4' } }

        expect_assigns(file: :file)
@ -82,7 +82,7 @@ describe SubmissionsController do
        end
      end

-      context 'for a non-binary file' do
+      context 'with a non-binary file' do
        let(:file) { submission.collect_files.detect {|file| file.file_type.file_extension == '.js' } }

        expect_assigns(file: :file)
@ -98,9 +98,10 @@ describe SubmissionsController do
  end

  describe 'GET #index' do
-    before(:all) { FactoryBot.create_pair(:submission) }
-
-    before { get :index }
+    before do
+      FactoryBot.create_pair(:submission)
+      get :index
+    end

    expect_assigns(submissions: Submission.all)
    expect_status(200)
@ -121,7 +122,7 @@ describe SubmissionsController do

      before { get :render_file, params: {filename: file.name_with_extension, id: submission.id} }

-      context 'for a binary file' do
+      context 'with a binary file' do
        let(:file) { submission.collect_files.detect {|file| file.file_type.file_extension == '.mp4' } }

        expect_assigns(file: :file)
@ -134,7 +135,7 @@ describe SubmissionsController do
        end
      end

-      context 'for a non-binary file' do
+      context 'with a non-binary file' do
        let(:file) { submission.collect_files.detect {|file| file.file_type.file_extension == '.js' } }

        expect_assigns(file: :file)
@ -154,12 +155,12 @@ describe SubmissionsController do
    let(:perform_request) { get :run, params: {filename: filename, id: submission.id} }

    before do
-      expect_any_instance_of(ActionController::Live::SSE).to receive(:write).at_least(3).times
+      allow_any_instance_of(ActionController::Live::SSE).to receive(:write).at_least(3).times
    end

    context 'when no errors occur during execution' do
      before do
-        expect_any_instance_of(DockerClient).to receive(:execute_run_command).with(submission, filename).and_return({})
+        allow_any_instance_of(DockerClient).to receive(:execute_run_command).with(submission, filename).and_return({})
        perform_request
      end

@ -222,7 +223,7 @@ describe SubmissionsController do
    let(:output) { {} }

    before do
-      expect_any_instance_of(DockerClient).to receive(:execute_test_command).with(submission, filename)
+      allow_any_instance_of(DockerClient).to receive(:execute_test_command).with(submission, filename)
      get :test, params: {filename: filename, id: submission.id}
    end

--- a/spec/db/seeds_spec.rb
+++ b/spec/db/seeds_spec.rb
@ -9,7 +9,9 @@ describe 'seeds' do
    CodeOcean::Application.load_tasks

    # We want to execute the seeds for the dev environment against the test database
+    # rubocop:disable Rails/Inquiry
    allow(Rails).to receive(:env) { 'development'.inquiry }
+    # rubocop:enable Rails/Inquiry
    allow(ActiveRecord::Base).to receive(:establish_connection).and_call_original
    allow(ActiveRecord::Base).to receive(:establish_connection).with(:development) {
      ActiveRecord::Base.establish_connection(:test)
--- a/spec/factories/code_ocean/file.rb
+++ b/spec/factories/code_ocean/file.rb
@ -16,7 +16,7 @@ module CodeOcean
      trait(:image) do
        association :file_type, factory: :dot_png
        name { 'poster' }
-        native_file { Rack::Test::UploadedFile.new(Rails.root.join('db', 'seeds', 'audio_video', 'poster.png'), 'image/png') }
+        native_file { Rack::Test::UploadedFile.new(Rails.root.join('db/seeds/audio_video/poster.png'), 'image/png') }
      end
    end

--- a/spec/factories/lti_parameter.rb
+++ b/spec/factories/lti_parameter.rb
@ -1,7 +1,7 @@
 # frozen_string_literal: true

 FactoryBot.define do
-  LTI_PARAMETERS = {
+  lti_params = {
    lis_result_sourcedid: 'c2db0c7c-4411-4b27-a52b-ddfc3dc32065',
      lis_outcome_service_url: 'http://172.16.54.235:3000/courses/0132156a-9afb-434d-83cc-704780104105/sections/21c6c6f4-1fb6-43b4-af3c-04fdc098879e/items/999b1fe6-d4b6-47b7-a577-ea2b4b1041ec/tool_grading',
      launch_presentation_return_url: 'http://172.16.54.235:3000/courses/0132156a-9afb-434d-83cc-704780104105/sections/21c6c6f4-1fb6-43b4-af3c-04fdc098879e/items/999b1fe6-d4b6-47b7-a577-ea2b4b1041ec/tool_return',
@ -12,10 +12,10 @@ FactoryBot.define do
    association :exercise, factory: :math
    association :external_user

-    lti_parameters { LTI_PARAMETERS }
+    lti_parameters { lti_params }

    trait :without_outcome_service_url do
-      lti_parameters { LTI_PARAMETERS.except(:lis_outcome_service_url) }
+      lti_parameters { lti_params.except(:lis_outcome_service_url) }
    end
  end
 end
--- a/spec/features/authorization_spec.rb
+++ b/spec/features/authorization_spec.rb
@ -3,7 +3,7 @@
 require 'rails_helper'

 describe 'Authorization' do
-  context 'as an admin' do
+  context 'when being an admin' do
    let(:user) { FactoryBot.create(:admin) }

    before { allow_any_instance_of(ApplicationController).to receive(:current_user).and_return(user) }
@ -13,7 +13,7 @@ describe 'Authorization' do
    end
  end

-  context 'as an external user' do
+  context 'with being an external user' do
    let(:user) { FactoryBot.create(:external_user) }

    before { allow_any_instance_of(ApplicationController).to receive(:current_user).and_return(user) }
@ -23,7 +23,7 @@ describe 'Authorization' do
    end
  end

-  context 'as a teacher' do
+  context 'with being a teacher' do
    let(:user) { FactoryBot.create(:teacher) }

    before { allow_any_instance_of(ApplicationController).to receive(:current_user).and_return(user) }
--- a/spec/features/editor_spec.rb
+++ b/spec/features/editor_spec.rb
@ -29,7 +29,7 @@ describe 'Editor', js: true do
    fill_in('email', with: user.email)
    fill_in('password', with: FactoryBot.attributes_for(:teacher)[:password])
    click_button(I18n.t('sessions.new.link'))
-    expect_any_instance_of(LtiHelper).to receive(:lti_outcome_service?).and_return(true)
+    allow_any_instance_of(LtiHelper).to receive(:lti_outcome_service?).and_return(true)
    visit(implement_exercise_path(exercise))
  end

--- a/spec/features/prometheus/controller_spec.rb
+++ b/spec/features/prometheus/controller_spec.rb
@ -7,8 +7,9 @@ describe Prometheus::Controller do
  let(:prometheus_config) { {prometheus_exporter: {enabled: true}} }

  def stub_metrics
+    metrics = %i[@instance_count @rfc_count @rfc_commented_count]
    %i[increment decrement observe].each do |method|
-      %i[@instance_count @rfc_count @rfc_commented_count].each do |metric|
+      metrics.each do |metric|
        allow(described_class.instance_variable_get(metric)).to receive(method)
      end
    end
--- a/spec/lib/assessor_spec.rb
+++ b/spec/lib/assessor_spec.rb
@ -11,7 +11,7 @@ describe Assessor do

    context 'when an error occurs' do
      before do
-        expect_any_instance_of(TestingFrameworkAdapter).to receive(:test_outcome).and_raise
+        allow_any_instance_of(TestingFrameworkAdapter).to receive(:test_outcome).and_raise
      end

      it 'catches the error' do
--- a/spec/lib/code_ocean/config_spec.rb
+++ b/spec/lib/code_ocean/config_spec.rb
@ -4,7 +4,7 @@ require 'rails_helper'

 describe CodeOcean::Config do
  describe '#read' do
-    let(:content) { {foo: 'bar'} }
+    let(:content) { {'foo' => 'bar'} }
    let(:filename) { :foo }

    context 'with a .yml file' do
--- a/spec/lib/docker_client_spec.rb
+++ b/spec/lib/docker_client_spec.rb
@ -3,8 +3,6 @@
 require 'rails_helper'
 require 'seeds_helper'

-# rubocop:disable RSpec/MultipleMemoizedHelpers
-
 WORKSPACE_PATH = Rails.root.join('tmp', 'files', Rails.env, 'code_ocean_test')

 describe DockerClient, docker: true do
@ -26,14 +24,14 @@ describe DockerClient, docker: true do
  describe '.check_availability!' do
    context 'when a socket error occurs' do
      it 'raises an error' do
-        expect(Docker).to receive(:version).and_raise(Excon::Errors::SocketError.new(StandardError.new))
+        allow(Docker).to receive(:version).and_raise(Excon::Errors::SocketError.new(StandardError.new))
        expect { described_class.check_availability! }.to raise_error(DockerClient::Error)
      end
    end

    context 'when a timeout occurs' do
      it 'raises an error' do
-        expect(Docker).to receive(:version).and_raise(Timeout::Error)
+        allow(Docker).to receive(:version).and_raise(Timeout::Error)
        expect { described_class.check_availability! }.to raise_error(DockerClient::Error)
      end
    end
@ -115,7 +113,7 @@ describe DockerClient, docker: true do

      context 'when retries are left' do
        before do
-          expect(described_class).to receive(:mapped_directories).and_raise(error).and_call_original
+          allow(described_class).to receive(:mapped_directories).and_raise(error).and_call_original
        end

        it 'retries to create a container' do
@ -125,7 +123,7 @@ describe DockerClient, docker: true do

      context 'when no retries are left' do
        before do
-          expect(described_class).to receive(:mapped_directories).exactly(DockerClient::RETRY_COUNT + 1).times.and_raise(error)
+          allow(described_class).to receive(:mapped_directories).exactly(DockerClient::RETRY_COUNT + 1).times.and_raise(error)
        end

        it 'raises the error' do
@ -140,7 +138,7 @@ describe DockerClient, docker: true do
    let(:container) { double }

    before do
-      expect(container).to receive(:binds).at_least(:once).and_return(["#{workspace_path}:#{DockerClient::CONTAINER_WORKSPACE_PATH}"])
+      allow(container).to receive(:binds).at_least(:once).and_return(["#{workspace_path}:#{DockerClient::CONTAINER_WORKSPACE_PATH}"])
    end

    after { docker_client.send(:create_workspace_files, container, submission) }
@ -183,11 +181,11 @@ describe DockerClient, docker: true do
    after { described_class.destroy_container(container) }

    it 'kills running processes' do
-      expect(container).to receive(:kill).and_return(container)
+      allow(container).to receive(:kill).and_return(container)
    end

    it 'releases allocated ports' do
-      expect(container).to receive(:port_bindings).at_least(:once).and_return(foo: [{'HostPort' => '42'}])
+      allow(container).to receive(:port_bindings).at_least(:once).and_return(foo: [{'HostPort' => '42'}])
      expect(PortPool).to receive(:release)
    end

@ -211,7 +209,7 @@ describe DockerClient, docker: true do
    end

    it 'sends the command' do
-      expect(docker_client).to receive(:send_command).with(command, kind_of(Docker::Container)).and_return({})
+      allow(docker_client).to receive(:send_command).with(command, kind_of(Docker::Container)).and_return({})
      execute_arbitrary_command
    end

@ -222,7 +220,7 @@ describe DockerClient, docker: true do
        let(:result) { {status: 'ok', stdout: 42} }

        before do
-          expect(docker_client).to receive(:send_command).and_raise(error).and_return(result)
+          allow(docker_client).to receive(:send_command).and_raise(error).and_return(result)
        end

        it 'retries to execute the command' do
@ -232,13 +230,13 @@ describe DockerClient, docker: true do

      context 'when no retries are left' do
        before do
-          expect(docker_client).to receive(:send_command).exactly(DockerClient::RETRY_COUNT + 1).times.and_raise(error)
+          allow(docker_client).to receive(:send_command).exactly(DockerClient::RETRY_COUNT + 1).times.and_raise(error)
        end

        it 'raises the error' do
          pending('retries are disabled')
-          # !TODO Retries is disabled
-          # expect { execute_arbitrary_command }.to raise_error(error)
+          # TODO: Retries is disabled
+          expect { execute_arbitrary_command }.to raise_error(error)
        end
      end
    end
@ -250,12 +248,10 @@ describe DockerClient, docker: true do
    after { docker_client.send(:execute_run_command, submission, filename) }

    it 'takes a container from the pool' do
-      pending('todo in the future')
      expect(DockerContainerPool).to receive(:get_container).with(submission.execution_environment).and_call_original
    end

    it 'creates the workspace files' do
-      pending('todo in the future')
      expect(docker_client).to receive(:create_workspace_files)
    end

@ -281,7 +277,7 @@ describe DockerClient, docker: true do

    it 'executes the test command' do
      expect(submission.execution_environment).to receive(:test_command).and_call_original
-      expect(docker_client).to receive(:send_command).with(kind_of(String), kind_of(Docker::Container)).and_return({})
+      allow(docker_client).to receive(:send_command).with(kind_of(String), kind_of(Docker::Container)).and_return({})
    end
  end

@ -305,7 +301,7 @@ describe DockerClient, docker: true do
    end

    context 'with incomplete configuration' do
-      before { expect(described_class).to receive(:config).at_least(:once).and_return({}) }
+      before { allow(described_class).to receive(:config).at_least(:once).and_return({}) }

      it 'raises an error' do
        expect { described_class.initialize_environment }.to raise_error(DockerClient::Error)
@ -357,7 +353,7 @@ describe DockerClient, docker: true do
  end

  describe '#send_command' do
-    let(:block) { proc {} }
+    let(:block) { proc { nil } }
    let(:container) { described_class.create_container(execution_environment) }
    let(:send_command) { docker_client.send(:send_command, command, container, &block) }

@ -379,8 +375,13 @@ describe DockerClient, docker: true do

    context 'when a timeout occurs' do
      before do
-        expect(container).to receive(:exec).once.and_raise(Timeout::Error)
-        expect(container).to receive(:exec).twice.and_return([[], []])
+        exec_called = 0
+        allow(container).to receive(:exec) do
+          exec_called += 1
+          raise Timeout::Error if exec_called == 1
+
+          [[], []]
+        end
      end

      it 'destroys the container asynchronously' do
@ -410,5 +411,3 @@ describe DockerClient, docker: true do
    end
  end
 end
-
-# rubocop:enable RSpec/MultipleMemoizedHelpers
--- a/spec/lib/docker_container_mixin_spec.rb
+++ b/spec/lib/docker_container_mixin_spec.rb
@ -11,7 +11,7 @@ describe DockerContainerMixin do
    end

    it 'returns the correct information' do
-      expect(CONTAINER).to receive(:json).and_return('HostConfig' => {'Binds' => binds})
+      allow(CONTAINER).to receive(:json).and_return('HostConfig' => {'Binds' => binds})
      expect(CONTAINER.binds).to eq(binds)
    end
  end
@ -25,7 +25,7 @@ describe DockerContainerMixin do
    end

    it 'returns the correct information' do
-      expect(CONTAINER).to receive(:json).and_return('HostConfig' => {'PortBindings' => port_bindings})
+      allow(CONTAINER).to receive(:json).and_return('HostConfig' => {'PortBindings' => port_bindings})
      expect(CONTAINER.port_bindings).to eq(port => port)
    end
  end
--- a/spec/lib/file_tree_spec.rb
+++ b/spec/lib/file_tree_spec.rb
@ -8,8 +8,8 @@ describe FileTree do
  describe '#file_icon' do
    let(:file_icon) { file_tree.send(:file_icon, file) }

-    context 'for a media file' do
-      context 'for an audio file' do
+    context 'with a media file' do
+      context 'with an audio file' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_mp3)) }

        it 'is an audio file icon' do
@ -17,7 +17,7 @@ describe FileTree do
        end
      end

-      context 'for an image file' do
+      context 'with an image file' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_jpg)) }

        it 'is an image file icon' do
@ -25,7 +25,7 @@ describe FileTree do
        end
      end

-      context 'for a video file' do
+      context 'with a video file' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_mp4)) }

        it 'is a video file icon' do
@ -34,8 +34,8 @@ describe FileTree do
      end
    end

-    context 'for other files' do
-      context 'for a read-only file' do
+    context 'with other files' do
+      context 'with a read-only file' do
        let(:file) { FactoryBot.build(:file, read_only: true) }

        it 'is a lock icon' do
@ -43,7 +43,7 @@ describe FileTree do
        end
      end

-      context 'for an executable file' do
+      context 'with an executable file' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_py)) }

        it 'is a code file icon' do
@ -51,7 +51,7 @@ describe FileTree do
        end
      end

-      context 'for a renderable file' do
+      context 'with a renderable file' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_svg)) }

        it 'is a text file icon' do
@ -59,7 +59,7 @@ describe FileTree do
        end
      end

-      context 'for all other files' do
+      context 'with all other files' do
        let(:file) { FactoryBot.build(:file, file_type: FactoryBot.build(:dot_md)) }

        it 'is a generic file icon' do
@ -100,7 +100,7 @@ describe FileTree do
    let!(:leaf) { root.add(Tree::TreeNode.new('', file)) }
    let(:root) { Tree::TreeNode.new('', file) }

-    context 'for a leaf node' do
+    context 'with a leaf node' do
      let(:node) { leaf }

      it 'produces the required attributes' do
@ -116,7 +116,7 @@ describe FileTree do
      end
    end

-    context 'for a non-leaf node' do
+    context 'with a non-leaf node' do
      let(:node) { root }

      it "traverses the node's children" do
@ -144,7 +144,7 @@ describe FileTree do
    let(:node_icon) { file_tree.send(:node_icon, node) }
    let(:root) { Tree::TreeNode.new('') }

-    context 'for the root node' do
+    context 'with the root node' do
      let(:node) { root }

      it 'is a folder icon' do
@ -152,7 +152,7 @@ describe FileTree do
      end
    end

-    context 'for leaf nodes' do
+    context 'with leaf nodes' do
      let(:node) { root.add(Tree::TreeNode.new('')) }

      it 'is a file icon' do
@ -161,7 +161,7 @@ describe FileTree do
      end
    end

-    context 'for intermediary nodes' do
+    context 'with intermediary nodes' do
      let(:node) do
        root.add(Tree::TreeNode.new('').tap {|node| node.add(Tree::TreeNode.new('')) })
      end
--- a/spec/lib/generators/testing_framework_adapter_generator_spec.rb
+++ b/spec/lib/generators/testing_framework_adapter_generator_spec.rb
@ -27,7 +27,7 @@ describe TestingFrameworkAdapterGenerator do

    it 'builds a correct class skeleton' do
      file_content = File.new(path, 'r').read
-      expect(file_content).to start_with("class #{name}Adapter < TestingFrameworkAdapter")
+      expect(file_content&.strip).to start_with("class #{name}Adapter < TestingFrameworkAdapter")
    end

    it 'generates a corresponding test' do
--- a/spec/lib/nonce_store_spec.rb
+++ b/spec/lib/nonce_store_spec.rb
@ -5,6 +5,10 @@ require 'rails_helper'
 describe NonceStore do
  let(:nonce) { SecureRandom.hex }

+  before do
+    stub_const('Lti::MAXIMUM_SESSION_AGE', 1)
+  end
+
  describe '.add' do
    it 'stores a nonce in the cache' do
      expect(Rails.cache).to receive(:write)
@ -28,8 +32,6 @@ describe NonceStore do
    end

    it 'returns false for expired nonces' do
-      Lti.send(:remove_const, 'MAXIMUM_SESSION_AGE')
-      Lti::MAXIMUM_SESSION_AGE = 1
      described_class.add(nonce)
      expect(described_class.has?(nonce)).to be true
      sleep(Lti::MAXIMUM_SESSION_AGE)
--- a/spec/lib/testing_framework_adapter_spec.rb
+++ b/spec/lib/testing_framework_adapter_spec.rb
@ -42,7 +42,7 @@ describe TestingFrameworkAdapter do

  describe '#test_outcome' do
    it 'calls the framework-specific implementation' do
-      expect(adapter).to receive(:parse_output).and_return(count: count, failed: failed, passed: passed)
+      allow(adapter).to receive(:parse_output).and_return(count: count, failed: failed, passed: passed)
      adapter.test_outcome('')
    end
  end
--- a/spec/models/code_ocean/file_spec.rb
+++ b/spec/models/code_ocean/file_spec.rb
@ -25,7 +25,7 @@ describe CodeOcean::File do
    expect(file.errors[:read_only]).to be_blank
  end

-  context 'as a teacher-defined test' do
+  context 'with a teacher-defined test' do
    before { file.update(role: 'teacher_defined_test') }

    it 'validates the presence of a feedback message' do
--- a/spec/models/execution_environment_spec.rb
+++ b/spec/models/execution_environment_spec.rb
@ -6,7 +6,7 @@ describe ExecutionEnvironment do
  let(:execution_environment) { described_class.create.tap {|execution_environment| execution_environment.update(network_enabled: nil) } }

  it 'validates that the Docker image works', docker: true do
-    expect(execution_environment).to receive(:validate_docker_image?).and_return(true)
+    allow(execution_environment).to receive(:validate_docker_image?).and_return(true)
    expect(execution_environment).to receive(:working_docker_image?)
    execution_environment.update(docker_image: FactoryBot.attributes_for(:ruby)[:docker_image])
  end
@ -124,22 +124,22 @@ describe ExecutionEnvironment do
  describe '#working_docker_image?', docker: true do
    let(:working_docker_image?) { execution_environment.send(:working_docker_image?) }

-    before { expect(DockerClient).to receive(:find_image_by_tag).and_return(Object.new) }
+    before { allow(DockerClient).to receive(:find_image_by_tag).and_return(Object.new) }

    it 'instantiates a Docker client' do
      expect(DockerClient).to receive(:new).with(execution_environment: execution_environment).and_call_original
-      expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_return({})
+      allow_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_return({})
      working_docker_image?
    end

    it 'executes the validation command' do
-      expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).with(ExecutionEnvironment::VALIDATION_COMMAND).and_return({})
+      allow_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).with(ExecutionEnvironment::VALIDATION_COMMAND).and_return({})
      working_docker_image?
    end

    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')
+        allow_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
@ -147,7 +147,7 @@ describe ExecutionEnvironment do

    context 'when the Docker client produces an error' do
      it 'adds an error' do
-        expect_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_raise(DockerClient::Error)
+        allow_any_instance_of(DockerClient).to receive(:execute_arbitrary_command).and_raise(DockerClient::Error)
        working_docker_image?
        expect(execution_environment.errors[:docker_image]).to be_present
      end
--- a/spec/models/exercise_spec.rb
+++ b/spec/models/exercise_spec.rb
@ -118,9 +118,7 @@ describe Exercise do
    end

    it 'duplicates all associated files' do
-      exercise.files.each do |file|
-        expect(file).to receive(:dup).and_call_original
-      end
+      expect(exercise.files).to all(receive(:dup).and_call_original)
    end

    it 'returns the duplicated exercise' do
--- a/spec/models/submission_spec.rb
+++ b/spec/models/submission_spec.rb
@ -34,7 +34,7 @@ describe Submission do
      before { submission.score = submission.exercise.maximum_score / 2 }

      it 'returns the score as a value between 0 and 1' do
-        expect(0..1).to include(submission.normalized_score)
+        expect(submission.normalized_score).to be_between(0, 1)
      end
    end

@ -54,7 +54,7 @@ describe Submission do
      before { submission.score = submission.exercise.maximum_score / 2 }

      it 'returns the score expressed as a percentage' do
-        expect(0..100).to include(submission.percentage)
+        expect(submission.percentage).to be_between(0, 100)
      end
    end

--- a/spec/policies/admin/dashboard_policy_spec.rb
+++ b/spec/policies/admin/dashboard_policy_spec.rb
@ -3,19 +3,19 @@
 require 'rails_helper'

 describe Admin::DashboardPolicy do
-  subject { described_class }
+  subject(:policy) { described_class }

  permissions :show? do
    it 'grants access to admins' do
-      expect(subject).to permit(FactoryBot.build(:admin), :dashboard)
+      expect(policy).to permit(FactoryBot.build(:admin), :dashboard)
    end

    it 'does not grant access to teachers' do
-      expect(subject).not_to permit(FactoryBot.build(:teacher), :dashboard)
+      expect(policy).not_to permit(FactoryBot.build(:teacher), :dashboard)
    end

    it 'does not grant access to external users' do
-      expect(subject).not_to permit(FactoryBot.build(:external_user), :dashboard)
+      expect(policy).not_to permit(FactoryBot.build(:external_user), :dashboard)
    end
  end
 end
--- a/spec/policies/code_ocean/file_policy_spec.rb
+++ b/spec/policies/code_ocean/file_policy_spec.rb
@ -3,86 +3,86 @@
 require 'rails_helper'

 describe CodeOcean::FilePolicy do
-  subject { described_class }
+  subject(:policy) { described_class }

  let(:exercise) { FactoryBot.create(:fibonacci) }
  let(:submission) { FactoryBot.create(:submission) }

  permissions :create? do
-    context 'as part of an exercise' do
+    context 'when being part of an exercise' do
      let(:file) { exercise.files.first }

      it 'grants access to admins' do
-        expect(subject).to permit(FactoryBot.build(:admin), file)
+        expect(policy).to permit(FactoryBot.build(:admin), file)
      end

      it 'grants access to authors' do
-        expect(subject).to permit(exercise.author, file)
+        expect(policy).to permit(exercise.author, file)
      end

      it 'does not grant access to all other users' do
        %i[external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), file)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), file)
        end
      end
    end

-    context 'as part of a submission' do
+    context 'when being part of a submission' do
      let(:file) { submission.files.first }

-      context 'where file creation is allowed' do
+      context 'when file creation is allowed' do
        before do
          submission.exercise.update(allow_file_creation: true)
        end

        it 'grants access to authors' do
-          expect(subject).to permit(submission.author, file)
+          expect(policy).to permit(submission.author, file)
        end
      end

-      context 'where file creation is not allowed' do
+      context 'when file creation is not allowed' do
        before do
          submission.exercise.update(allow_file_creation: false)
        end

        it 'grants access to authors' do
-          expect(subject).not_to permit(submission.author, file)
+          expect(policy).not_to permit(submission.author, file)
        end
      end

      it 'does not grant access to all other users' do
        %i[admin external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), file)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), file)
        end
      end
    end
  end

  permissions :destroy? do
-    context 'as part of an exercise' do
+    context 'when being part of an exercise' do
      let(:file) { exercise.files.first }

      it 'grants access to admins' do
-        expect(subject).to permit(FactoryBot.build(:admin), file)
+        expect(policy).to permit(FactoryBot.build(:admin), file)
      end

      it 'grants access to authors' do
-        expect(subject).to permit(exercise.author, file)
+        expect(policy).to permit(exercise.author, file)
      end

      it 'does not grant access to all other users' do
        %i[external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), file)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), file)
        end
      end
    end

-    context 'as part of a submission' do
+    context 'when being part of a submission' do
      let(:file) { submission.files.first }

      it 'does not grant access to anyone' do
        %i[admin external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), file)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), file)
        end
      end
    end
--- a/spec/policies/consumer_policy_spec.rb
+++ b/spec/policies/consumer_policy_spec.rb
@ -3,14 +3,14 @@
 require 'rails_helper'

 describe ConsumerPolicy do
-  subject { described_class }
+  subject(:policy) { described_class }

  %i[create? destroy? edit? index? new? show? update?].each do |action|
    permissions(action) do
      it 'grants access to admins only' do
-        expect(subject).to permit(FactoryBot.build(:admin), Consumer.new)
+        expect(policy).to permit(FactoryBot.build(:admin), Consumer.new)
        %i[external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), Consumer.new)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), Consumer.new)
        end
      end
    end
--- a/spec/policies/execution_environment_policy_spec.rb
+++ b/spec/policies/execution_environment_policy_spec.rb
@ -3,22 +3,22 @@
 require 'rails_helper'

 describe ExecutionEnvironmentPolicy do
-  subject { described_class }
+  subject(:policy) { described_class }

  let(:execution_environment) { FactoryBot.build(:ruby) }

  [:index?].each do |action|
    permissions(action) do
      it 'grants access to admins' do
-        expect(subject).to permit(FactoryBot.build(:admin), execution_environment)
+        expect(policy).to permit(FactoryBot.build(:admin), execution_environment)
      end

      it 'grants access to teachers' do
-        expect(subject).to permit(FactoryBot.build(:teacher), execution_environment)
+        expect(policy).to permit(FactoryBot.build(:teacher), execution_environment)
      end

      it 'does not grant access to external users' do
-        expect(subject).not_to permit(FactoryBot.build(:external_user), execution_environment)
+        expect(policy).not_to permit(FactoryBot.build(:external_user), execution_environment)
      end
    end
  end
@ -26,16 +26,16 @@ describe ExecutionEnvironmentPolicy do
  %i[execute_command? shell? statistics? show?].each do |action|
    permissions(action) do
      it 'grants access to admins' do
-        expect(subject).to permit(FactoryBot.build(:admin), execution_environment)
+        expect(policy).to permit(FactoryBot.build(:admin), execution_environment)
      end

      it 'grants access to authors' do
-        expect(subject).to permit(execution_environment.author, execution_environment)
+        expect(policy).to permit(execution_environment.author, execution_environment)
      end

      it 'does not grant access to all other users' do
        %i[external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), execution_environment)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), execution_environment)
        end
      end
    end
@ -44,16 +44,16 @@ describe ExecutionEnvironmentPolicy do
  %i[destroy? edit? update? new? create?].each do |action|
    permissions(action) do
      it 'grants access to admins' do
-        expect(subject).to permit(FactoryBot.build(:admin), execution_environment)
+        expect(policy).to permit(FactoryBot.build(:admin), execution_environment)
      end

      it 'does not grant access to authors' do
-        expect(subject).not_to permit(execution_environment.author, execution_environment)
+        expect(policy).not_to permit(execution_environment.author, execution_environment)
      end

      it 'does not grant access to all other users' do
        %i[external_user teacher].each do |factory_name|
-          expect(subject).not_to permit(FactoryBot.build(factory_name), execution_environment)
+          expect(policy).not_to permit(FactoryBot.build(factory_name), execution_environment)
        end
      end
    end
--- a/Show More
+++ b/Show More