问题描述

如果我在测试中包含永远不会到达的代码(例如，promise 序列的 fail 子句)，我该如何强制测试失败?

If I have code in a test that should never be reached (for example the fail clause of a promise sequence), how can I force-fail the test?

我使用类似 expect(true).toBe(false); 之类的东西，但这并不漂亮.

I use something like expect(true).toBe(false); but this is not pretty.

另一种方法是等待测试超时，我想避免这种情况(因为它很慢).

The alternative is waiting for the test to timeout, which I want to avoid (because it is slow).

推荐答案

Jasmine 提供了一个全局方法 fail()，可以在 spec 块中使用 it()并且还允许使用自定义错误消息:

Jasmine provides a global method fail(), which can be used inside spec blocks it() and also allows to use custom error message:

it('should finish successfully', function (done) {
  MyService.getNumber()
  .success(function (number) {
    expect(number).toBe(2);
    done();
  })
  .fail(function (err) {
    fail('Unwanted code branch');
  });
});

这是 Jasmine 的内置功能，与我在下面提到的错误"方法相比，它在任何地方都能正常工作.

This is built-in Jasmine functionality and it works fine everywhere in comparison with the 'error' method I've mentioned below.

更新前:

您可以从该代码分支抛出错误，它会立即使规范失败，您将能够提供自定义错误消息:

You can throw an error from that code branch, it will fail a spec immediately and you'll be able to provide custom error message:

it('should finish successfully', function (done) {
  MyService.getNumber()
  .success(function (number) {
    expect(number).toBe(2);
    done();
  })
  .fail(function (err) {
    throw new Error('Unwanted code branch');
  });
});

但是你应该小心，如果你想从 Promise 成功处理程序 then() 抛出一个错误，因为错误会被吞没在那里并且永远不会出现.此外，您应该注意应用程序中可能存在的错误处理程序，它们可能会在您的应用程序中捕获此错误，因此它不会导致测试失败.

But you should be careful, if you want to throw an error from Promise success handler then(), because the error will be swallowed in there and will never come up. Also you should be aware of the possible error handlers in your app, which might catch this error inside your app, so as a result it won't be able to fail a test.

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