如何使用TypeScript和mocha进行异步/等待测试

Question

我有一个简单的异步mocha测试,但done()似乎永远不会调用回调.

describe("RiBot", function() {
  it("should start with a random topic", async (done) => {
    await RiBot.init();
    let topic = RiBot.getTopic("testuser")
    assert.equal(topic, "FAILHERE");
    done()
  })
})

在这种情况下,断言应该失败,但我只是暂停.

  RiBot
  RibotTest topic +0ms undefined
    1) should start with a random topic


  0 passing (2s)
  1 failing

  1) RiBot should start with a random topic:
     Error: timeout of 2000ms exceeded. Ensure the done() callback is being called in this test.

编辑:当我使用断言运行标准JS代码时:

async function testRiBot() {
  try {
    await RiBot.init()
    let topic = RiBot.getTopic("testuser")
    debug('topic', topic)
    assert.equal(topic, "FAILHERE", 'fail match on topic');
  } catch(err) {
    debug("err", err, err.stack)
  }
}

我确实得到一个异常抛出的错误.

  RibotTest err +2ms { [AssertionError: fail match on topic]
  name: 'AssertionError',
  actual: 'undefined',
  expected: 'FAILHERE',
  operator: '==',
  message: 'fail match on topic',
  generatedMessage: false } AssertionError: fail match on topic
    at /Users/dc/dev/rikai/boteditor/test/RiBot_test.js:19:20
    at next (native)
    at fulfilled (/Users/dc/dev/rikai/boteditor/test/RiBot_test.js:4:58)
    at process._tickCallback (node.js:412:9)

有人可以使用打字稿async/await和mocha提供一个简单的例子吗？

Answer 1

尝试像这样定义你的测试......(同时删除完成的调用)

it('should start with a random topic', async function () {
    // ...
});

请注意,如果您的测试返回Promise,那么mocha框架将查找要解析或拒绝的Promise而不是完成回调.注意异步函数始终返回Promise.

此外,最佳做法是避免使用箭头函数来定义测试,否则您无法this从测试中访问正确的上下文(即,您无法执行this.title在测试代​​码中调用的操作).