(module test-concurrency "sicp-concurrency.ss"
  (define (test-1)
    (define x 10)
    (parallel-execute (lambda () (set! x (* x x)))
                      (lambda () (set! x (+ x 1))))
    x)
  
  (define (test-2)
    (define x 10)
    (define s (make-serializer))
    (parallel-execute (s (lambda () (set! x (* x x))))
                      (s (lambda () (set! x (+ x 1)))))
    x))