I've talked before about unit testing (here, and here). My premise is that in addition to being an important industry technique, it's a sound practice for students studying CS. I also contend that it can make grading easier on the teacher. Maybe not as easy as an auto-grader but those have their own problems.
Since I spent most of today grading I thought I'd share my current workflow and how unit tests have made me more efficient.
I have each student make a single GitHub repo for all individual homeworks, labs and small projects. They'll make additional repos for larger and group projects. They fill out a Google form to give me the repo link. I download the form and end up with a CSV file something like this:
Doe, John, firstname.lastname@example.org:johndoe/mymoework.git Doe, Jane, email@example.com:janedoe/labs.git etc.
My goal is to clone each students repo into a directory and then throughout the term, they add assignments to their own repos using the names and specifications I give them. For example, after assigning three assignments, I could pull everything from their repos and I would have a directory structure something like this:
hw ├── doe_jane │ ├── hw_01 │ ├── hw_02 │ └── hw_03 │ └── doe_john ├── hw_01 └── hw_02
To get there, I have to change the csv file to a small shell script:
git clone firstname.lastname@example.org:johndoe/mymoework.git doe_john git clone email@example.com:janedoe/labs.git doe_jane etc.
I usually do this in Emacs with a macro.
Now I'm ready to go.
Whenever there's a new assignment, I just have to update all the repos. I go into the root hw directory and loop through all the subdirectoryes:
cs /path/to/hw_root for i in `ls` do cd /path/to/hw_root/$i git pull done
At this point I could go into each repo but we can do better. Since I
have all of my students submit a Makefile with a default target to
build an executable named
main and also a target named
will build an executable to run the unit tests named
tests I do this
instead of a straight pull:
cs /path/to/hw_root for i in `ls` do cd /path/to/hw_root/$i git pull cd hw_03 # or whatever assignment I'm grading make tests make done
Now, if I want, I can go into each directory, run the tests by typing
./tests and the hw or project with
./main. I can also add a
couple of lines to the for loop above like:
echo "$i Test Report\n----------------\n" >> /path/to/hw_root/test_report ./tests >> /path/to/hw_root/test_rport echo "----------------------\n\n"
This gives me a single file with everyone's test results. Either by doing this or by running the tests in each folder manually I can quickly see what works and what doesn't.
While I'm doing this, I have Emacs up and with dired mode and more specifically ag-dired-regexp which lets me easily navigate to any student's files. Combined with the test results I can quickly evaluate the entire assignment.
Put all of this together and it makes grading somewhat bearable. I can work through well written, correct assignments extremely quickly and drill down into the other projects efficiently as well.