## Introduction

The gradeR package helps grade your students’s assignment submissions that are R Scripts (.r or .R files). If you want to use gradeR for grading submissions on your own laptop or desktop, please see the vignette here. Instead, this vignette describes how to use the Gradescope autograder with a helper function from gradeR.

If you have already read the “getting started” vignette, and you work for an institution/university that has an appropriate subscription to this service, then this is probably useful information for you.

For each assignment you make, you might consider cloning this repository, modifying the student-facing assignment provided in example_hw_assignment/, and then modifying the files required by Gradescope provided in autograding_code_and_data/.

## A High-Level view

Students submit their assignments to Gradescope, and afterwards, their code is run and checked on Gradescope servers. The benefit is that students get feedback much more quickly, and your computer doesn’t need to stay busy all day running student code.

The downside is that everything becomes a bit more complicated–but that’s what this repository is for. It provides a template for each assignment: both the student-facing assignment description, as well as the the code you have to give Gradescope.

The autograding code for each Gradescope assignment is comprised of several files. This repository has provided all of these files in the directory autograding_code_and_data.

1. setup.sh is a Linux Bash script that the Gradescope servers run to install R and any R packages that are required. For those of you have little to no experience with shell scripting, do not despair! This repository provides an example file (see here) that will be easy to modify. Note that the name of this file must be setup.sh because that is what Gradescope expects.

2. The file with all of the tests. This can have any name you want, and it will usually change depending on what assignment you’re grading. In this example, we call it assignment1_grading_file.r. This file contains testthat tests, which is another R package that gradeR depends on. The example should be pretty self explanatory, but for those looking for more detail, see the original gradeR vignette, or the documentation for the testthat package. Note that by default, each test case has its visibility set to “after_due_date.” If you would like a test to be visible to the students before the deadline has passed, make sure to include the phrase (visible) in the name of the particular test. Other options include (hidden) and (after_published). For more information on visibility options, see the Gradescope documentation available here.

3. The .R file that grades a single student submission. This can be named anything you want, too, but we call it grade_one_submission.r. Thanks to gradeR, this one is pretty simple–it just calls gradeR::calcGradesForGradescope(). This function runs a single student’s .R file submission, checks it against the provided testthat tests, and nicely formats the output in a way that Gradescope expects.

4. run_autograder is another Bash script that Gradescope’s Linux servers run. This file must have this name, because Gradescope expects this. This small program is run every time a single student submission needs to be graded. It copies a single student submission into the directory that the Gradescope server expects, and then it runs the previously-mentioned file (grade_one_submission.R).

5. Extra data files need to be included too. For example, our example homework assignment asked students to read in the file called data.csv. This particular csv file can be found in our directory with all the other autograding files.

After all of these files have been written, they are then compressed into a single .zip file (as described by Gradescope here), and then uploaded to Gradescope. Gradescope takes care of the rest.

Note that it is still possible to use Gradescope’s autograder without the gradeR package. For an example of how to do that, please see this Github repo.

## Customization Checklist

To make your own assignment, log on to Gradescope and then start a new programming assignment. Then, download/clone this repository and make some customizations to the files. After you have made the changes, zip those files up, and upload it to Gradescope.

A word of warning: uploading the zip file can take several minutes.

If you are unfamiliar with their website, please see the instructions that they provide here.

There are a few things to do when you customize this to your own assignment:

1. Make sure that each student’s submission is named the same. In our example, we assume all submissions are named assignment1.R

2. Make sure grade_one_submission.r references the correct filenames. For us, we chose assignment1.R and assignment1_tests.R

3. Make sure your assignment instructions feature the same warnings in our example assignment here. This isn’t absolutely required, but it is helpful for the students.

4. Make sure your setup.sh installs all packages that student code requires.

5. Make sure run_autograder uses the correct filenames. The directories are what Gradescope expects, so don’t change those.

6. Double check your test visibilities. Remember, by default all tests are only shown after the due date has passed. If you would like a test to be visible, just insert the phrase “(visible)” into the name of the test file. For example, that is done on the first test here.. Personally, I usually make a few of the easy tests visible, just to make sure that students know before the deadline that “Gradescope” was able to run their script successfully.

7. Make sure the max score you enter on Gradescope is the same as the total number of tests you have.