🪶Grading with Maven

Overview

This guide shows how to set up a Maven-based Java programming assignment in CodeGrade, using instructor-written JUnit tests and AutoTest for automated grading.

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Configuring AutoTest Setup

Install Java and Maven

In AutoTest > Setup:

• Add the Install Java block (or use the script below).

• Add a Script block to install Java 17, Maven 3.8.4, and junitparser:

sudo apt update
sudo apt install openjdk-17-jre -y

wget https://archive.apache.org/dist/maven/maven-3/3.8.4/binaries/apache-maven-3.8.4-bin.tar.gz -P /tmp/
sudo tar xf /tmp/apache-maven-3.8.4-bin.tar.gz -C /opt
sudo ln -s /opt/apache-maven-3.8.4/ /opt/maven
sudo rm /usr/bin/mvn
sudo ln -s /opt/maven/bin/mvn /usr/bin/mvn

pip3 install junitparser

AutoTest Setup for Maven assignments

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Configuring AutoTest Tests

1. Upload and prepare instructor tests

• Upload your test files using an Upload Files block (e.g., CircleTest.java).

• Use a Script block to move them:

mkdir -p src/test/java/com/example/shapes
cp $UPLOADED_FILES/*.java src/test/java/com/example/shapes

Block student-submitted test files in General Settings > Hand-in Requirements (e.g., deny *Test.java).

Upload and prepare tests

2. Prepare build and classpath

Add a Script block to compile and collect dependencies:

#!/usr/bin/env bash
set -euo pipefail

mvn -q -DskipTests=true clean package
mvn -q dependency:copy-dependencies -DoutputDirectory=target/dependency -DincludeScope=test

DEP_JARS="$(ls target/dependency/*.jar 2>/dev/null | tr '\n' ':' || true)"
SELF_JAR="$(ls target/*.jar 2>/dev/null | tr '\n' ':' || true)"
JAR_PATHS="${DEP_JARS}${SELF_JAR}target/classes:target/test-classes"
CG_CP="$(cg junit5 get-classpath || true)"

echo "export CLASSPATH=\"${JAR_PATHS}${CG_CP:+:${CG_CP}}:.\"" >> ~/.cg_bash_env
echo 'export MAIN_CLASS="com.example.Main"' >> ~/.cg_bash_env

This ensures all compiled classes and dependencies are available to the test phase.

3. Running Maven tests

Use Connect Rubric + Custom Test blocks for each test class. Each test block can link to a separate rubric category for grading.

mvn -q -Dtest=CircleTest test || true
cg junitxml target/surefire-reports/TEST-CircleTest.xml

The project is compiled during the setup phase. Maven automatically skips recompilation when there are no changes.

Running Maven tests

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Troubleshooting Maven Autograding in CodeGrade

This section lists common issues you may encounter when setting up Maven-based Java assignments in CodeGrade, along with quick solutions.

Maven or Java not found

Symptom: AutoTest logs show mvn: command not found or java: command not found

Fix:

• Ensure Java and Maven are installed in the Setup phase.

• Double-check the setup script includes the correct symbolic links to Maven:

sudo ln -s /opt/maven/bin/mvn /usr/bin/mvn

Tests not detected

Symptom: Maven runs without executing any tests.

Fixes:

• Ensure test class names match *Test.java or *Tests.java.

• Confirm test files are copied into src/test/java/...

• If tests use packages, ensure folders match package structure.

• Use the -Dtest=ClassName flag to target specific test classes in test blocks.

Test failures without output

Symptom: AutoTest runs but doesn’t show detailed feedback.

Fix:

• Verify cg junitxml target/surefire-reports/*.xml is included after mvn test.

• Ensure the Surefire plugin outputs XML (default behavior).

• Avoid cleaning (mvn clean) between test blocks unless needed.

Classpath errors or missing dependencies

Symptom: ClassNotFoundException or build errors for imported classes.

Fixes:

• Run mvn dependency:copy-dependencies -DincludeScope=test in Setup.

• Confirm your pom.xml includes required dependencies.

• Use the environment setup script to populate CLASSPATH.

Timeouts or hanging tests

Symptom: Tests hang or AutoTest fails due to long execution.

Fixes:

• Use JUnit timeouts (e.g., @Test(timeout = 2000) or assertTimeout() for JUnit 5).

• Review student code for infinite loops or blocking I/O.

• Set step-level timeouts in AutoTest test block settings.

Still Need Help?

For assistance with custom cases, reach out to [email protected] and share a relevant snapshot or example submission.