javascript - 如何期待与 Mocha 和 Chai 的 throw ？

Question

我无法找到用 Mocha 和 Chai 捕捉抛出的绳子的解决方案

正在测试的代码:

function SimpleDate(year, month, day) {
    if (!isValidDate(year, month, day)) {
        throw "invalid date";
    }
}

测试代码:

it("returns 'invalid date' for year = 2023, month = 13, day = 55", function () {
    let actual = new DateUtils.SimpleDate(2013, 13, 55);
    //let expected ='invalid date';
    let expected = expect(() => DateUtils.SimpleDate(2013, 13, 55)).to.throw('invalid date');


    assert.equal(actual, expected);
});

我希望测试能够通过，但我尝试的代码失败，提示“错误:抛出了字符串“无效日期”，抛出错误:)”

Answer 1

事实证明，解决方案是定义一个包装函数来调用您正在测试的函数，然后将包装函数传递给assert.throws

it("returns 'invalid date' for year = 2023, month = 13, day = 55", function () {
    let year = 2013,
        month = 13,
        day = 55;
    let expectedMessage = 'invalid date';
    let wrapper = function () {
        let x = DateUtils.SimpleDate(year, month, day);
    }

    assert.throws(wrapper, expectedMessage);
});