(define test-1
  (lambda ()
    (let ((e '((lambda (x y z) (x y z 1)))))
      (equal? e (unparse (parse e))))))

(define test-2
  (lambda ()
    (let ((e '(lambda (x) 'x)))
      (equal? e (unparse (parse e))))))

(define test-3
  (lambda ()
    (let ((e '(if (let ((x 1)) x)
                  (let* ((x 2)) x)
                  (letrec ((x 3)) x))))
      (equal? e (unparse (parse e))))))

(define test-4
  (lambda ()
    (let ((e '(lambda (x y) (x a 1 b)))
          (fv (set 'a 'b)))
      (set= fv (free-vars (parse e))))))

(define test-5
  (lambda ()
    (let ((e '(let ((x y) (y x)) (x y)))
          (fv (set 'x 'y)))
      (set= fv (free-vars (parse e))))))

(define test-6
  (lambda ()
    (let ((e '(let* ((a b) (b a)) (a b)))
          (fv (set 'b)))
      (set= fv (free-vars (parse e))))))

(define test-7
  (lambda ()
    (let ((e '(letrec ((s t) (t s)) (s t)))
          (fv (set)))
      (set= fv (free-vars (parse e))))))

(define test-8
  (lambda ()
    (let ((e '(if (let ((x y) (y x)) (x y))
                  (let* ((a b) (b a)) (a b))
                  (letrec ((s t) (t s)) (s t))))
          (fv (set 'x 'y 'b)))
      (set= fv (free-vars (parse e))))))

(define test-9
  (lambda ()
    (let ((e '(lambda (x y) (x a y b)))
          (bv (set 'x 'y)))
      (set= bv (bound-vars (parse e))))))

(define test-10
  (lambda ()
    (let ((e '(if (let ((x y) (y x)) (x y))
                  (let* ((a b) (b a)) (a b))
                  (letrec ((s t) (t s)) (s t))))
          (bv (set 'x 'y 'a 'b 's 't)))
      (set= bv (bound-vars (parse e))))))