Update sinon to > 6.1.1

[prateekbh]

What's the issue?

I am trying to add a tests for a file of mine which uses XHR. In order to do this, I tried setting up a small testfile for my code and mocked the XHR in exact same way as https://github.com/ampproject/amphtml/blob/master/test/functional/test-xhr.js#L76-L93.

Adding this in a filename test-document-fetcher.js in test/functional folder lead to breaking of test in test-preconnect.js which modifies XHRHttpRequest.prototype https://github.com/ampproject/amphtml/blob/master/test/functional/test-preconnect.js#L88

I tried removing as much code as possible from my test, which made me zero down the cause to using sandbox.useFakeXMLHttpRequest().

Looks like there was a bug in sinon itself: sinonjs/sinon#1840

And was fixed in 6.1.1

How do we reproduce the issue?

1. Make a file test-dummy.js in test/functional folder.
2. Use sandbox.useFakeXMLHttpRequest() in it and write a dummy test around XMLHttpRequest.
3. Allow travis to run this in saucelabs.
4. test-preconnect.js will fail.

What browsers are affected?

None

Which AMP version is affected?

Not sure

[rsimha]

@prateekbh Let me know if useFakeXMLHttpRequest works now.

[prateekbh]

@rsimha thank you for the work. Sadly it didn't solved what I was looking for.

I made a dummy PR to repro this: #17263

[rsimha]

What's the problem? I can get that test and others to pass.

[prateekbh]

Everything's fine on local machine, it goes to travis -> saucelabs and breaks test-preconnect.js which is not even touched in this PR

[prateekbh]

https://travis-ci.org/ampproject/amphtml/jobs/411485802

[rsimha]

Seems like your test isn't properly mocking the global XMLHttpRequest, so you'll need to make sure that's being done correctly. If you can't get it to work, please file a separate issue.

See https://stackoverflow.com/a/33978113