LibTest/core/int/operator_subtraction_A01_t01.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion num operator -(num other)
/// This operator implements arithmetic subtraction operation.
/// @description Checks that this operator returns correct value for both integer 
/// and double arguments (including special values).
/// @author vasya

import "../../../Utils/expect.dart";
import "dart:math" as Math;

main() {
  Expect.equals(0, 1 - 1);
  Expect.equals(2147483646, 2147483647 - 1);
  Expect.equals(-2147483649, -2147483648 - 1);
  Expect.equals(4294967294, 4294967295 - 1);
  Expect.equals(-4294967297, -4294967296 - 1);
  Expect.equals(9007199254740990, 9007199254740991 - 1);
  Expect.equals(-9007199254740991, -9007199254740990 - 1);
  Expect.equals(1, 9007199254740991 - 9007199254740990);

  final double MIN_DOUBLE = Math.pow(2.0, -1074) as double;
  final double NEG_MIN_DOUBLE = -1 * MIN_DOUBLE; 
  final double MAX_DOUBLE =
      (2 - Math.pow(2.0, -52)) * Math.pow(2.0, 1023) as double;
  final double NEG_MAX_DOUBLE = -1 * MAX_DOUBLE; 

  Expect.equals(0.0, 0 - 0.0);
  Expect.equals(0.0, 0 - -0.0);
  Expect.equals(0.0, 1 - 1.0);
  Expect.equals(0.0, -1 - -1.0);

  Expect.equals(double.negativeInfinity, 0 - double.infinity);
  Expect.equals(double.infinity, 0 - double.negativeInfinity);
  Expect.equals(NEG_MIN_DOUBLE, 0 - MIN_DOUBLE);
  Expect.equals(NEG_MAX_DOUBLE, 0 - MAX_DOUBLE);

  Expect.isTrue((0 - double.nan).isNaN);
}