(library (tests numerics)
  (export run-tests)
  (import (ikarus))

  (define (test-rounding)
    (define (test-round x)
      (let ([rx (round x)])
        (unless (integer? rx)
          (error 'test-round "not an integer result for" x rx))
        (let ([diff (abs (- (abs x) (abs rx)))])
          (cond
            [(= diff 1/2) 
             (unless (even? rx)
               (error 'test-round "non-even rounding for" x rx))]
            [else
             (unless (< diff 1/2)
               (error 'test-round "rounding the wrong way for" x rx))]))))
    (test-round -251/100)
    (test-round -250/100)
    (test-round -249/100)
    (test-round +251/100)
    (test-round +250/100)
    (test-round +249/100)

    (test-round -151/100)
    (test-round -150/100)
    (test-round -149/100)
    (test-round +151/100)
    (test-round +150/100)
    (test-round +149/100)

    (test-round -351/100)
    (test-round -350/100)
    (test-round -349/100)
    (test-round +351/100)
    (test-round +350/100)
    (test-round +349/100)
    
    (test-round +0.00)
    (test-round -0.00)
    (test-round +0.49)
    (test-round -0.49)
    (test-round +1.49)
    (test-round -1.49)
    (test-round +2.49)
    (test-round -2.49)
    (test-round +3.49)
    (test-round -3.49)
    (test-round +0.51)
    (test-round -0.51)
    (test-round +1.51)
    (test-round -1.51)
    (test-round +2.51)
    (test-round -2.51)
    (test-round +3.51)
    (test-round -3.51)
    (test-round +0.50)
    (test-round -0.50)
    (test-round +1.50)
    (test-round -1.50)
    (test-round +2.50)
    (test-round -2.50)
    (test-round +3.50)
    (test-round -3.50)



    )

  (define (test-eqv)
    (define (test-eqv x y result)
      (unless (eqv? (eqv? x y) result) 
        (error 'test-eqv "failed" x y result)))
    (test-eqv 0 0 #t)
    (test-eqv 0.0 0 #f)
    (test-eqv 0 0.0 #f)
    (test-eqv 0.0 0.0 #t)
    (test-eqv 0.0 -0.0 #f)
    (test-eqv -0.0 0.0 #f)
    (test-eqv -0.0 -0.0 #t)
    ;;; ikarus extensions, not guaranteed by R6RS
    (test-eqv +nan.0 +nan.0 #t)
    (test-eqv (/ +inf.0 +inf.0) (/ -inf.0 +inf.0) #t)
    (test-eqv +nan.0 (string->number "+nan.0") #t))

  (define (test-exact-integer-sqrt)
    (define (f i j inc)
      (when (< i j)
        (let-values ([(s r) (exact-integer-sqrt i)])
          (unless (and (= (+ (* s s) r) i)
                       (< i (* (+ s 1) (+ s 1))))
            (error 'exact-integer-sqrt "wrong result" i))
          (f (+ i inc) j inc))))
    (f 0 10000 1)
    (f 0 536870911 10000)
    (f 0 536870911000 536870911))


  (define (run-tests)
    (test-rounding)
    (test-exact-integer-sqrt)
    (test-eqv))
  )