Your test cases should run with JUnit 3.8.1. Let's assume this is installed on your account under /usr/local/junit3.8.1. JUnit may not be added by default to your classpath on your account. (Check first.) In this case you must add junit.jar to your classpath. There are several ways to do this, depending on exactly what shell or development environment you are using:
setenv CLASSPATH .:/usr/local/junit3.8.1/junit.jar
(Notice the . on the path, which tells Java to process files in the current directory.)
javac -classpath .:/usr/local/junit3.8.1/junit.jar StudentTests.java java -classpath .:/usr/local/junit3.8.1/junit.jar junit.textui.TestRunner StudentTests
You can update your classpath permanently by modifying .cshrc (for csh variants) or .bashrc (for bash). If the files do not exist, you can create them in your home directory using any text editor. If you want to write your project at home, you'll need to download JUnit 3.8.1 from the JUnit web page.