function shouldBe(actual, expected) { if (actual !== expected) throw new Error('bad value: ' + actual); } noInline(shouldBe); 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)}`); } noInline(shouldThrow); function test(description) { return Symbol(description); } noInline(test); var count = 0; var flag = false; var object = { toString() { count++; if (flag) { throw new Error("out"); } return "Cocoa"; } }; for (var i = 0; i < 1e4; ++i) { shouldBe(test(object).description, "Cocoa"); shouldBe(count, i + 1); } flag = true; shouldThrow(() => { shouldBe(test(object).description, "Cocoa"); shouldBe(count, 1e4 + 1); }, `Error: out`);