Question

所以这是我试图用casperjs和mocha解决的问题。我试图在页面上测试元素的文本值，以查看它是否在... 5-10秒的时间内更新。我的想法是抓住值，将其推入数组，等待500毫秒并重复直到数组有20个项目。那是大约10秒钟。然后在数组上运行下划线/ lodash的_.uniq函数，并测试数组长度为> 1。

我遇到的问题是mocha没有等待这个完成，因为说明测试是成功/失败。我以为我可以增加摩卡的超时时间，但这没有任何区别。请参阅下面的代码。我已经评论了它的可读性。

it('has elements whose values update', function () {
  // 20 seconds, which should be plenty of time
  this.timeout(20000);

  casper.then(function() {
        // The test array
    var values = [],
        // So we can stop the intervals
        intervalId;

    function getValue () {
      // Grab element's text value
      var value = casper.evaluate(function () { return $('#element').text(); });

      // Push in to our test array
      values.push(value);

      // 20 * 500ms == 10 seconds or 10000ms
      // When set to 500ms, this block never runs. The test passes before it has a chance to
      if (values.length === 20) {

        // Stop it from checking the value any further
        clearInterval(intervalId);

        // Test to see we've had more than one unique value in the 10 seconds
        expect(_.uniq(values).length).to.be.gt(1);
      } 
    } 

    // Wait for the value on the page to populate
    // It defaults to '-' when the page loads
    casper.waitFor(function () {
      return this.evaluate(function () {
        return $('#element').text() !== '-';
      });

    // Start the check with a delay of 500ms between each check
    }, function then() {
      intervalId = setInterval(getValue, 500);
    });
  });
});

当间隔值设置为500ms时，在mocha进入下一个测试之前，我在values中得到2-3个元素值。甚至更奇怪的是，当我确定测试通过时，他们在摩卡上的屏幕上打印console.log(values)。原因是values.length永远不会达到10，因此永远不会调用expect调用。假设测试通过。以下是500毫秒间隔的测试输出：

Dashboard
✓ has elements whose values update (202ms)
Values: ["20,832,022"]
Values: ["20,832,022","20,832,372"]
Values: ["20,832,022","20,832,372","20,832,722"]

✓ has the page title of leads (41ms)

2 passing (11s)

即使没有20件物品也会通过。由于某处超时，它永远不会检查它。这是50ms间隔的输出：

Dashboard

✓ has elements whose values update (341ms)
Values: ["20,400,667"]
Values: ["20,400,667","20,400,718"]
Values: ["20,400,667","20,400,718","20,400,718"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820","20,400,820"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820","20,400,820","20,400,871"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820","20,400,820","20,400,871","20,400,871"]
Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820","20,400,820","20,400,871","20,400,871","20,400,922"]
Final Values: ["20,400,667","20,400,718","20,400,718","20,400,769","20,400,769","20,400,820","20,400,820","20,400,871","20,400,871","20,400,922"]

✓ has the page title of leads (41ms)

2 passing (8s)

我用50ms获得更多，但这只是测试的半秒。页面上的其他一些值需要更长的时间才能更新到此状态。

我已经尝试将done回调传递给it语句，但是mocha忽略它并且不等待它被调用。

这是工具的限制还是我使用它们错了？

我尝试使用以下方法完成回调。

it('has elements whose values update', function (done) {

和

expect(_.uniq(values).length).to.be.gt(1);
done();

我仍然忽略了我将测试标记为异步。在500ms时它仍然通过而没有进入if语句或完成调用。在50ms时会抛出此错误：

done() called multiple times

我正在使用mocha-casperjs。这会影响它吗？

Answer 1

似乎mocha-casperjs没有使用默认的done。它知道测试步骤已经完成，因为它使用了CasperJS＆＃39;控制流。在您的情况下，您可以通过getValue调用setInterval来突破控制流程。

最好重构代码以使用getValue的递归调用：

function getValue () {
  // Grab element's text value
  var value = this.evaluate(function () { return $('#element').text(); });

  // Push in to our test array
  values.push(value);

  // 20 * 500ms == 10 seconds or 10000ms
  // When set to 500ms, this block never runs. The test passes before it has a chance to
  if (values.length === 20) {
    // Test to see we've had more than one unique value in the 10 seconds
    expect(_.uniq(values).length).to.be.gt(1);
  } else {
    this.wait(500, getValue);
  }
} 

// Wait for the value on the page to populate
// It defaults to '-' when the page loads
casper.waitFor(function () {
  return this.evaluate(function () {
    return $('#element').text() !== '-';
  });

// Start the check with a delay of 500ms between each check
}, function then() {
  this.wait(500, getValue);
});

这使getValue成为一个步骤。

另一个没有太多重构的解决方案是让第二个waitFor沿着破坏的控制流的一侧运行。这需要一个半全局变量someGlobalVariable。也许intervalId可以用于此，但最好在顶部使用someGlobalVariable = false;。

intervalId = setInterval(getValue, 500);
this.waitFor(function check(){
    return someGlobalVariable;
}, function then(){
   // do something else
}, null, 20000);

让它停止

expect(_.uniq(values).length).to.be.gt(1);
someGlobalVariable = true;

运行CasperJS测试时，Mocha不尊重超时或完成回调

1 个答案: