// 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.

// @dart = 2.9

/// @assertion double acos(num x)
/// Converts x to a double and returns its arc cosine in radians.
/// Throws an error if [x] is null.
/// @description Checks that Error is thrown when an argument is a null (not
/// a number).
/// @author msyabro
/// @reviewer pagolubev
/// @needsreview undocumented


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

main() {
  Expect.throws(() {
    Math.acos(null);
  });
}