Write down your answers (and why you chose them!) in your group’s shared doc.
In this week’s lab you will write an automatic “grader” for some of the methods we worked on in week 3.
In particular, you’ll write a script and a test file that gives a score to the functionality of a student-submitted
ListExamples file and class (see ListExamples.java). The specific format is that you’ll write a
bash script that takes the URL of a Github repository and prints out a grade:
$ bash grade.sh https://github.com/some-username/some-repo-name ... messages about points ...
This will work with a test file that you write in order to grade students’ work. You can use this repository to get started with your grader implementation; you should make a fork:
As part of your work, you’ll need to add new tests (or copy them from your work from lab 3) to the testing file, because the few tests that are there aren’t sufficient for grading. You can do that incrementally as you try out the script you write below on different student submissions.
Do the work below in pairs—as a pair, you should produce one implementation—push it to one member’s fork of the starter Github repository and include the link to that repository in your notes.
When your script gets a student submission it should produce either:
A general workflow for your script could be:
.javafile with the grading tests, and any other files the script needs into the
grading-areadirectory is created for you, but you should move the files there.
cp(also look up the
javac, useful tools here are output redirection and error codes (
$?) along with
set -e. Why?
grepcould be helpful here
Work incrementally – make sure you understand what the given code does. Then add steps incrementally. After each step, run on a test student submission and check for syntax errors, debug that step, add
echo statements to check what’s stored in variables, and so on. Try running it more than once – is there any set up or cleanup you need to do before or after running it? Don’t write the whole thing. Refer to lecture from Monday to see some ways Joe did this incrementally in class.
Write down in notes screenshots of what your grader does on each of the sample student cases below.
Assume the assignment spec was to submit:
static List<String> filter(List<String> s, StringChecker sc)
static List<String> merge(List<String> list1, List<String> list2)
You should use the following repositories to test your grader:
filterin the wrong order, so it doesn’t match the expected behavior.
assertSame, which compares with
.equals(), and think hard about duplicates for
After you’re satisfied with the behavior on all of those submissions, write your own. Try to come up with at least two examples:
You should create these as new, public Github repositories, so that you can run them using the same grader script by providing the Github URL.
Write down in notes: Run everyone’s newly-developed student submissions on everyone’s grader. That means each team should be running commands like
bash grade.sh <student-submission-from-some-group>
Whose grading script is the most user-friendly across those tests?
We’ve also provided our
Server.java and a server we wrote for you called
GradeServer.java in the starter repository.
You can compile them and use
java GradeServer 4000
to run the server.
Look at the code to understand the expected path and parameters in
GradeServer.java. Loading a URL at the
/grade path with one of the repos above as the query parameter. What happens?
That’s quite a bit of the way towards an autograder like Gradescope!
Write down in notes: Show a screenshot of the server running your autograder in a browser.
Discuss and write down: What other features are needed to make this work more like Gradescope’s autograder? (Think about running for different students, storing grades, presenting results, etc)
Congratulations! You’ve done one kind of the work that your TAs do when setting up classes 🙂