;;
;; FILE:     homework06-tests.rkt
;; AUTHOR:   Eugene Wallingford
;; DATE:     2025/03/04
;; COMMENT:  This file loads "homework06.rkt" and runs tests on its
;;           publicly-defined functions.  I copied the tests from
;;           the 2021/03/10 version of homework06-tests.rkt in the
;;           2023 Homework 6 solutions file.
;;
;; MODIFIED: 
;; CHANGE:   
;;

#lang racket
(require rackunit)
(require "homework06.rkt")

;; --------------------------------------------------------------------------
;; Problem 1                                           (structural recursion)
;; --------------------------------------------------------------------------

(check-equal? (list-index 'd '())
              -1)
(check-equal? (list-index 'a '(a c b e d f d))
              0)
(check-equal? (list-index 'd '(a b c d e f d))
              3)
(check-equal? (list-index 'g '(a b c d e f d))
              -1)

;; --------------------------------------------------------------------------
;; Problem 2                                           (structural recursion)
;; --------------------------------------------------------------------------

(check-equal? (tree-sum 8)
              8)
(check-equal? (tree-sum '(8 9 10))
              27)
(check-equal? (tree-sum '(1 (2 3 4) 5))
              15)
(check-equal? (tree-sum '(1 2 (3 4 5)))
              15)
(check-equal? (tree-sum '(8 (13 11 (5 24 6)) (15 (12 10 14) 20)))
              138)

;; --------------------------------------------------------------------------
;; Problem 3                                           (structural recursion)
;; --------------------------------------------------------------------------

(check-true  (tree? '1))
(check-true  (tree? '(8 (13 11 (5 24 6)) (15 (12 10 14) 20))))
(check-false (tree? 'x))
(check-false (tree? '(1 (2 3 4) (2 3 4 5))))
(check-false (tree? '(8 (13 x (5 24 6)) (15 (12 10 14) 20))))

;; --------------------------------------------------------------------------
;; Problem 4                                                (little language)
;; --------------------------------------------------------------------------

(check-false (unused-var? 'x 'x))
(check-false (unused-var? 'x 'y))
(check-false (unused-var? 'x '(x y)))
(check-true  (unused-var? 'x '(lambda (x) y)))
(check-false (unused-var? 'x '(lambda (x) x)))
(check-false (unused-var? 'x '(lambda (y) (lambda (x) x))))
(check-true  (unused-var? 'y '(lambda (y) (lambda (x) x))))
(check-true  (unused-var? 'x '(lambda (x) (lambda (x) x))))
(check-true  (unused-var? 'y '(lambda (z) (lambda (y) (lambda (x) x)))))
(check-false (unused-var? 'x '(a (lambda (z) (lambda (y) (lambda (x) x))))))
(check-true  (unused-var? 'z '(z (lambda (z) (lambda (y) (lambda (x) x))))))

;; --------------------------------------------------------------------------