(define sample
  (dat:json-parse
   "{\"title\":\"dat \\\"thang\\\"\",\"items\":[true,false,null,-2,1.25e2],\"line\":\"a\\nb\"}"))
(unless (equal? (dat:json-object-ref sample "title") "dat \"thang\"")
  (error 'test-failed "JSON strings and escaped quotes"))
(unless (equal? (dat:json-object-ref sample "items")
                '(json:array #t #f json:null -2 125.0))
  (error 'test-failed "JSON arrays, literals, and numbers"))
(unless (equal? (dat:json-object-ref sample "line") "a\nb")
  (error 'test-failed "JSON escaped newline"))
(unless (equal? (dat:json-parse "\"\\uD83D\\uDE00\"")
                (list->string (map integer->char '(#xf0 #x9f #x98 #x80))))
  (error 'test-failed "JSON UTF-16 surrogate pair"))
(unless (json:number-token? "-0.4E+3")
  (error 'test-failed "valid JSON number"))
(when (json:number-token? "+1")
  (error 'test-failed "reject Scheme-only number spelling"))
(let* ((wire '(json:object ("type" . "chat/text")
                           ("content" . (json:object ("channel" . "general")
                                                     ("text" . "hello\n🐬")))
                           ("timestamp" . 42)))
       (encoded (dat:json-stringify wire))
       (decoded (dat:json-parse encoded)))
  (unless (equal? (dat:json-object-ref decoded "type") "chat/text")
    (error 'test-failed "S-expression JSON adapter object roundtrip"))
  (unless (equal? (dat:json-object-ref
                   (dat:json-object-ref decoded "content") "text") "hello\n🐬")
    (error 'test-failed "S-expression JSON adapter escaped Unicode string")))
(let ((caught #f))
  (catch #t
    (lambda () (dat:json-parse "[1,]"))
    (lambda args (set! caught #t)))
  (unless caught (error 'test-failed "reject trailing array comma")))
(display "S7 JSON/S-expression adapter: PASS\n")