$ cat ~/tmp/test-stats.scm 
(import (chicken file)
        (chicken pathname)
        (chicken process-context))

(let ((egg-files (command-line-arguments))
      (eggs-with-tests 0)
      (depend-on-test 0)
      (no-test-deps 0))
  (for-each
   (lambda (egg-file)
     (let* ((egg-data (with-input-from-file egg-file read))
            (has-tests?
             (file-exists?
              (make-pathname (list (pathname-directory egg-file) "tests")
                             "run.scm")))
            (test-deps (alist-ref 'test-dependencies egg-data eq? '())))
       (when has-tests?
         (set! eggs-with-tests (+ eggs-with-tests 1))
         (when (memq 'test test-deps)
           (set! depend-on-test (+ depend-on-test 1)))
         (when (null? test-deps)
           (set! no-test-deps (+ no-test-deps 1))))))
   egg-files)

  (print "Eggs with tests: " eggs-with-tests)
  (print "Eggs with tests that depend on the test egg: " depend-on-test)
  (print "Eggs with tests that do not depend on the test egg: "
         (- eggs-with-tests depend-on-test))
  (print "Eggs with tests that don't depend on any egg: " no-test-deps)
  )



$ csi -s ~/tmp/test-stats.scm $(ls */*/*.egg)
Eggs with tests: 253
Eggs with tests that depend on the test egg: 200
Eggs with tests that do not depend on the test egg: 53
Eggs with tests that don't depend on any egg: 30