CSC/ECE 517 Spring 2017/oss E1713

E1713. Refactor penalty_helper.rb and late_policies_controller.rb
This project is intended to improve the code quality and reduce technical debt within the Expertiza system by refactoring the penalty_helper.rb module, refactoring the late_policies_controller.rb controller, and adding test coverage for both files.

Introduction

Expertiza

Expertiza is an open source web application which allows an instructor to manage assignments. It has various features viz. creating new assignments, customizing existing assignments, automatically allocating submissions for peer review etc. It has been developed using the Ruby on Rails framework, and the code is available on Github.

Project Goals

In this project, the files late_policies_controller.rb and penalty_helper.rb were to be refactored. The methods contained in these files were too long, and needed to be either shortened, or used polymorphically, or deleted altogether if they were not being used. They also were to be refactored semantically if the code did not follow good Ruby coding practices.

Late policies and penalties functionality

After an instructor creates an assignment in Expertiza they will have the ability to edit the details of the assignment by clicking the Edit action icon beside the assignment. From the "Editing Assignment" screen instructors have the ability to set due dates for each round of an assignment on the "Due dates" tab. On this tab, the instructor can elect to apply a late policy to the assignment by checking the "Apply penalty policy" checkbox and selecting a late policy from the adjacent drop down menu. If no late policies exist, or if the instructor wishes to define a new late policy, then they can click the "New late policy" link to define a new late policy.

An instructor can define a late policy with the following fields: Late policy name - This name will show up in the drop down menu on the "Due dates" tab when editing the assignment. It is not enforced to be unique. Penalty Unit - With the options of 'Minute', 'Hour', and 'Day' this field will define the frequency with which penalty points are deducted if an assignment is submitted after a due date. Penalty Point Per Unit - This is the amount of points which will be deducted from the student's score for the assignment round every time the Penalty Unit time has elapsed between the due date and the submission date. [Range: > 50] Maximum Penalty - Points will continue to be deducted from the assignment round score for each Penalty Unit time that has elapsed, but the number of points deducted will not exceed the Maximum Penalty [Range: 1..50]

Change specifics

The penalty_helper.rb and late_policies_controller.rb files are central to the creation and maintenance of late policies. Late policies are created by instructors and associated with assignments. The late_policies_controller.rb file is primarily used in the communication with view where late policies are displayed, created, or modified. The penalty_helper.rb file includes many useful methods related to late policies and the penalties which result from their use. For instance, if an assignment is designated as having penalties calculated then when it is graded the PenaltyHelper module will allow the penalties for each assignment to be calculated and applied to the final grade for the assignment.

This effort was initiated with the intent of refactoring some longer methods with redundant subprocedures so that the overall structure of the code is cleaner, concise, and DRYer. This was achieved by performing analysis on the files to identify methods which are not used within the Expertiza code base, methods which are too long, and redundant code which can be extracted from other methods and replaced with a call to a single method.

late_policies.controller.rb

Specific changes identified and made here, including the motivation behind making those changes.

penalty_helper.rb

This is a helper class which contains methods which calculate the different penalties, and are then brought together in one Hash object. The aim was to keep the methods below 25 lines of code if possible. Out of the numerous methods in the file, there were 3 substantial methods, namely calculate_penalty, calculate_submission_penalty, and compute_penalty_on_reviews crossed the 25 line limit.

Functional and integration testing

Motivation behind testing including the technologies used for testing.

penalty_helper_spec.rb

Specific changes identified and made here, including the motivation behind making those changes.

late_policies_controller_spec.rb

Specific changes identified TO BE made here, including the motivation behind making those changes.

Peer review validation

Instructions on how our reviewers should validate the impacted functionality to ensure that it still works.