;; *** Numbers ***

(defonce DELTA 1e-12)

(deftest test-add
  (are (= _1 _2)
      (+) 0
      (+ 1) 1
      (+ 1 2) 3
      (+ 1 2 3) 6

      (+ -1) -1
      (+ -1 -2) -3
      (+ -1 +2 -3) -2

      (+ 1 -1) 0
      (+ -1 1) 0

      (+ 2/3) 2/3
      (+ 2/3 1) 5/3
      (+ 2/3 1/3) 1 )

  (are (< (- _1 _2) DELTA)
      (+ 1.2) 1.2
      (+ 1.1 2.4) 3.5
      (+ 1.1 2.2 3.3) 6.6 )

  (is (> (+ Integer/MAX_VALUE 10) Integer/MAX_VALUE))  ; no overflow
  (is (thrown? ClassCastException (+ "ab" "cd"))) )    ; no string concatenation


(deftest test-subtract
  (is (thrown? IllegalArgumentException (-)))
  (are (= _1 _2)
      (- 1) -1
      (- 1 2) -1
      (- 1 2 3) -4

      (- -2) 2
      (- 1 -2) 3
      (- 1 -2 -3) 6

      (- 1 1) 0
      (- -1 -1) 0

      (- 2/3) -2/3
      (- 2/3 1) -1/3
      (- 2/3 1/3) 1/3 )

  (are (< (- _1 _2) DELTA)
      (- 1.2) -1.2
      (- 2.2 1.1) 1.1
      (- 6.6 2.2 1.1) 3.3 )

  (is (< (- Integer/MIN_VALUE 10) Integer/MIN_VALUE)) )  ; no underflow


(deftest test-multiply
  (are (= _1 _2)
      (*) 1
      (* 2) 2
      (* 2 3) 6
      (* 2 3 4) 24

      (* -2) -2
      (* 2 -3) -6
      (* 2 -3 -1) 6

      (* 1/2) 1/2
      (* 1/2 1/3) 1/6
      (* 1/2 1/3 -1/4) -1/24 )

  (are (< (- _1 _2) DELTA)
      (* 1.2) 1.2
      (* 2.0 1.2) 2.4
      (* 3.5 2.0 1.2) 8.4 )

  (is (> (* 3 (int (/ Integer/MAX_VALUE 2.0))) Integer/MAX_VALUE)) )  ; no overflow


(deftest test-divide
  (are (= _1 _2)
      (/ 1) 1
      (/ 2) 1/2
      (/ 3 2) 3/2
      (/ 4 2) 2
      (/ 24 3 2) 4
      (/ 24 3 2 -1) -4

      (/ -1) -1
      (/ -2) -1/2
      (/ -3 -2) 3/2
      (/ -4 -2) 2
      (/ -4 2) -2 )

  (are (< (- _1 _2) DELTA)
      (/ 4.5 3) 1.5
      (/ 4.5 3.0 3.0) 0.5 )

  (is (thrown? ArithmeticException (/ 0)))
  (is (thrown? ArithmeticException (/ 2 0)))
  (is (thrown? IllegalArgumentException (/))) )