Coffee is a simple autograder for Java programs I made at during a hackathon. It compares the output produced by the functions in a Java program against expected input. For any test cases that did not match expected results, the program prints out the diffs in the command line. It also supports methods that call functions that read from user input.
This was my first time doing any sort of shell scripting and working with the command line (beyond just installing and running things), so it was a fun experience!