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Resources for Programming Course TA?
cndrr asks: "I'm a Teacher's Assistant for intro to Java at my university again this fall. The last time I taught, all the TAs had students turn in their assignments through email. I'm thinking about scripting a site that will let students turn in their programs automatically and in some cases, run the program and (based on the output) automatically grade it. Has anyone else TAed and found a good solution that they would recommend?"
As we try to teach our students, use the best tool for the job. In my opinion, that means only using automated testing when necessary. I am teaching a course (Programming in C & the UNIX Environment) the first time this summer. (I was fortunate enough to be granted a research assistantship when I was accepted to grad school, so I was never a grader.) I was offered the use of some automatic collection and grading scripts developed by someone in the department decades ago, but I decided to avoid them.
In my case, grading does not constitute a significant percentage of my teaching and prep work. I only have 5 students in the class. Although this system would have saved me some time, I remembered my own experiences with a professor when I was an undergraduate. I do not know whether or not this professor used automatic testing, but he was rather draconian about things being written exactly the way that he would have written them and that they produce exactly the output that he envisioned. Unfortunately, I have learned from trying to complete his assignments and from my experiences in industry that it is extremely difficult to completely and unambiguously write a specification document. Furthermore, I wanted my students to be able to use their creativity in their assignments -- I instruct them, for example, that their program should produce certain pieces of data as their output, and that these should be organized in some tabular form, but I do not require that their output look exactly like mine. Thus, automated testing would be of little use.
That said, you asked for resources, not to be talked out of it, and I assume your situation is significantly different from mine that the benefits of automation outweigh the drawbacks. The collection part is easy; either write a script they can call to copy their files to some specified destination, or write one that goes out at the submission deadline and copies from a standard location in their home directories. On UNIX, require the students to include a makefile with the all target. I am not very familiar with Java, but I presume they have a similar cross-platform approach. Assuming that all of the programs read from standard input and write to standard output, the testing part is also rather straightforward. Write your own implementation of the assignment. (An important step in any case!) Write some input files as test cases, capture your implementation's output for each of them, and then compare them to the output produced by the students' code with diff. For added security, do the entire compilation and testing steps in a chroot environment.
If you adopt this though, remember that you still have to look through everyone's code, even the ones that pass all tests. Hopefully you are grading for style in addition to correctness, and you need to verify that students aren't plagiarizing each other.
Good luck