test: fix flaky test-regress-GH-897

Even after being moved to `sequential` in
1ce05ad540, `test-regress-GH-897` still
was occasionally flaky on Raspberry Pi devices on CI.

The test is especially sensitive to resource constraints. It failed
reliably on my laptop if I moved it to `parallel` and ran 32 competing
node test processes. Even for a flaky test, that's unusually low. I
typically don't see problems, even for flaky tests, until I get up to
around four times that number.

On a Raspberry Pi, of course, that sensitivity to resource constraints
will manifest much sooner.

This change checks the order of timers firing, rather than the duration
before a timer is fired. This eliminates the sensitivity to resource
constraints. The test can now be moved back to `parallel`. I am able to
run many copies of the test simultaneously without seeing test failures.

PR-URL: https://github.com/nodejs/node/pull/10903
Fixes: https://github.com/nodejs/node/issues/10073
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
pull/10960/head
Rich Trott 2017-01-19 11:19:07 -08:00
parent 067be658f9
commit 80c72c6d55
2 changed files with 20 additions and 17 deletions

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@ -0,0 +1,20 @@
'use strict';
// Test for bug where a timer duration greater than 0 ms but less than 1 ms
// resulted in the duration being set for 1000 ms. The expected behavior is
// that the timeout would be set for 1 ms, and thus fire before timers set
// with values greater than 1ms.
//
// Ref: https://github.com/nodejs/node-v0.x-archive/pull/897
const common = require('../common');
let timer;
setTimeout(function() {
clearTimeout(timer);
}, 0.1); // 0.1 should be treated the same as 1, not 1000...
timer = setTimeout(function() {
common.fail('timers fired out of order');
}, 2); // ...so this timer should fire second.

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@ -1,17 +0,0 @@
'use strict';
// Test for bug where a timer duration greater than 0 ms but less than 1 ms
// resulted in the duration being set for 1000 ms. The expected behavior is
// that the timeout would be set for 1 ms, and thus fire more-or-less
// immediately.
//
// Ref: https://github.com/nodejs/node-v0.x-archive/pull/897
const common = require('../common');
const assert = require('assert');
const t = Date.now();
setTimeout(common.mustCall(function() {
const diff = Date.now() - t;
assert.ok(diff < 100, `timer fired after ${diff} ms`);
}), 0.1);