| function shouldThrow(func, errorMessage) { |
| var errorThrown = false; |
| var error = null; |
| try { |
| func(); |
| } catch (e) { |
| errorThrown = true; |
| error = e; |
| } |
| if (!errorThrown) |
| throw new Error('not thrown'); |
| if (String(error) !== errorMessage) |
| throw new Error(`bad error: ${String(error)}`); |
| } |
| |
| let a = function() {}; |
| Object.defineProperty(a, Symbol.hasInstance, { value: Atomics }); |
| let b = a.bind(); |
| shouldThrow(() => { |
| Function.prototype[Symbol.hasInstance].call(b) |
| }, `TypeError: function [Symbol.hasInstance] is not a function, undefined, or null`); |