This is a shell for Java autograder assignments with test classes for GitHub Classroom with codespaces and maven. It requires a newer version of maven compatible with Java 17. It works locally and in a Codespace. The devcontainer.json specifies a container with Java 17 and (hopefully) a compatible version of maven.

I'm just learning this stuff so pull requests to this repo are welcome.

To use it, make a fork and rename/refactor/add stuff to make it into the starter code for your assignment and the test cases. Maybe change this readme file into your homework instructions. Right now I don't know how to hide test cases from students or prevent them from modifying the test cases or actions. So check the diffs when they push and make sure they aren't being sneaky. Make the repo a template repository in settings and then use it to create an assignment in GitHub Classroom.

Refactor App.java to the main file for the assignment. Refactor AppTest and AnotherAppTest to be unit test classes. In GitHub Classroom, add mvn test -Dtest=AppTest to run the first, and mvn test -Dtest=AnotherAppTest to run the second. Create additional files full of tests for additional partial credit.

Alternatively, for Classroom, you can make one test class with carefully named tests according to a pattern, then run them in groups in separate calls to give partial credit. e.g. mvn test -Dtest=AppTest#xxx, where xxx is a method name or pattern. So if you, for example, prefix all tests for part 1 with part1, like public void part1testGetter, part1testSetter, part1testConstructor, you can run all those with mvn test -Dtest=AppTest#part1* and assign a point value for just those.

For testing standard input/output, an example test is given for a main method that computes the sum of two integers. Be careful with line separators, and with clearing streams if you are testing multiple separate input/output items. It's definitely not the best way to test but often necessary before students learn how to write methods.

UPDATE ok this is dumb, but the default java version used by the autograder runner is 11, not 17. This makes maven crash. To change this, you have to edit the yml file. But this file is only generated by GitHub classroom when you create the assignment from the template repo! I found a workaround here.

1. Create an assignment with autograding setup as you would want
2. Accept the assignment yourself. Grab the .github/workflows/classroom.yml and .github/classroom/autograding.json files
3. Change the workflow to include the setup-java action
4. Add the files to your template repository
5. Recreate the assignment and do not setup autograding

Here's what the classroom.yml file looks like after this update:

name: GitHub Classroom Workflow

on: [push]

permissions:
  checks: write
  actions: read
  contents: read

jobs:
  build:
    name: Autograding
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-java@v3
        with:
          distribution: 'temurin'
          java-version: '17'
          cache: 'maven'
      - uses: education/autograding@v1