practracker: Add unit tests to test script, and test script to makefile

This makes all of the practracker tests get run by make check, and
hence by our CI.

Closes ticket 31304.

scripts/maint/practracker/test_practracker.sh

@@ -29,6 +29,10 @@ run_practracker() {
         "${DATA}/" "$@";
 }
 
+echo "unit tests:"
+
+"${PYTHON:-python}" "${PRACTRACKER_DIR}/practracker_tests.py" || exit 1
+
 echo "ex0:"
 
 run_practracker --exceptions "${DATA}/ex0.txt" > "${TMPDIR}/ex0-received.txt"