test(devtools): Fix intermittent DevTools API test timeout

[ExE-Boss]

This fixes the intermittent timeout issue that caused a #171 test to fail.

External links:

• https://travis-ci.org/mozilla/webextension-polyfill/builds/487787360#L950

[Rob--W]

What makes you think that 1000ms fixes the issue (where 500ms did not)? The test waits for the devtools page to initialize. I would not be surprised if this takes more than a second on very slow machines (in rare cases). What about raising the timeout to, say, 3 seconds? It's still relatively low, but significantly more than 0.5 or 1 second.

[Rob--W]

Your patch doesn't work because the test function is defined here, without return value:

webextension-polyfill/test/fixtures/tape-standalone.js

Lines 12 to 18 in 949f08c

	// Export as a global a wrapped test function which enforces a timeout by default.
	window.test = (desc, fn) => {
	tape(`${desc} (${browser})`, async (t) => {
	t.timeoutAfter(DEFAULT_TIMEOUT);
	await fn(t);
	});
	};

To fix this, I think that you can use the timeout option instead of explicitly calling timeoutAfter, see https://github.com/substack/tape/blob/v4.5.0/readme.markdown#testname-opts-cb and _timeout / timeoutAfter in https://github.com/substack/tape/blob/v4.5.0/lib/test.js

[Rob--W]

@ExE-Boss Have you already made some changes? The PR hasn't been updated yet.

[Rob--W]

Almost there!

[Rob--W]

Thanks for your patch.