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test: refactor event-emitter-check-listener-leaks

* add block-scoping
* use common.mustCall() on callbacks that should not execute

PR-URL: #13164
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
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Trott authored and jasnell committed May 22, 2017
1 parent efae43f commit c4502728fb99263128bbe11c36430070bb8baa19
Showing with 63 additions and 57 deletions.
  1. +63 −57 test/parallel/test-event-emitter-check-listener-leaks.js
@@ -25,73 +25,79 @@ const common = require('../common');
const assert = require('assert');
const events = require('events');

let e = new events.EventEmitter();

// default
for (let i = 0; i < 10; i++) {
e.on('default', common.noop);
}
assert.ok(!e._events['default'].hasOwnProperty('warned'));
e.on('default', common.noop);
assert.ok(e._events['default'].warned);
{
const e = new events.EventEmitter();

// symbol
const symbol = Symbol('symbol');
e.setMaxListeners(1);
e.on(symbol, common.noop);
assert.ok(!e._events[symbol].hasOwnProperty('warned'));
e.on(symbol, common.noop);
assert.ok(e._events[symbol].hasOwnProperty('warned'));
for (let i = 0; i < 10; i++) {
e.on('default', common.mustNotCall());
}
assert.ok(!e._events['default'].hasOwnProperty('warned'));
e.on('default', common.mustNotCall());
assert.ok(e._events['default'].warned);

// specific
e.setMaxListeners(5);
for (let i = 0; i < 5; i++) {
e.on('specific', common.noop);
}
assert.ok(!e._events['specific'].hasOwnProperty('warned'));
e.on('specific', common.noop);
assert.ok(e._events['specific'].warned);
// symbol
const symbol = Symbol('symbol');
e.setMaxListeners(1);
e.on(symbol, common.mustNotCall());
assert.ok(!e._events[symbol].hasOwnProperty('warned'));
e.on(symbol, common.mustNotCall());
assert.ok(e._events[symbol].hasOwnProperty('warned'));

// specific
e.setMaxListeners(5);
for (let i = 0; i < 5; i++) {
e.on('specific', common.mustNotCall());
}
assert.ok(!e._events['specific'].hasOwnProperty('warned'));
e.on('specific', common.mustNotCall());
assert.ok(e._events['specific'].warned);

// only one
e.setMaxListeners(1);
e.on('only one', common.noop);
assert.ok(!e._events['only one'].hasOwnProperty('warned'));
e.on('only one', common.noop);
assert.ok(e._events['only one'].hasOwnProperty('warned'));
// only one
e.setMaxListeners(1);
e.on('only one', common.mustNotCall());
assert.ok(!e._events['only one'].hasOwnProperty('warned'));
e.on('only one', common.mustNotCall());
assert.ok(e._events['only one'].hasOwnProperty('warned'));

// unlimited
e.setMaxListeners(0);
for (let i = 0; i < 1000; i++) {
e.on('unlimited', common.noop);
// unlimited
e.setMaxListeners(0);
for (let i = 0; i < 1000; i++) {
e.on('unlimited', common.mustNotCall());
}
assert.ok(!e._events['unlimited'].hasOwnProperty('warned'));
}
assert.ok(!e._events['unlimited'].hasOwnProperty('warned'));

// process-wide
events.EventEmitter.defaultMaxListeners = 42;
e = new events.EventEmitter();
{
events.EventEmitter.defaultMaxListeners = 42;
const e = new events.EventEmitter();

for (let i = 0; i < 42; ++i) {
e.on('fortytwo', common.noop);
}
assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
e.on('fortytwo', common.noop);
assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
delete e._events['fortytwo'].warned;
for (let i = 0; i < 42; ++i) {
e.on('fortytwo', common.mustNotCall());
}
assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
e.on('fortytwo', common.mustNotCall());
assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
delete e._events['fortytwo'].warned;

events.EventEmitter.defaultMaxListeners = 44;
e.on('fortytwo', common.noop);
assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
e.on('fortytwo', common.noop);
assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
events.EventEmitter.defaultMaxListeners = 44;
e.on('fortytwo', common.mustNotCall());
assert.ok(!e._events['fortytwo'].hasOwnProperty('warned'));
e.on('fortytwo', common.mustNotCall());
assert.ok(e._events['fortytwo'].hasOwnProperty('warned'));
}

// but _maxListeners still has precedence over defaultMaxListeners
events.EventEmitter.defaultMaxListeners = 42;
e = new events.EventEmitter();
e.setMaxListeners(1);
e.on('uno', common.noop);
assert.ok(!e._events['uno'].hasOwnProperty('warned'));
e.on('uno', common.noop);
assert.ok(e._events['uno'].hasOwnProperty('warned'));
{
events.EventEmitter.defaultMaxListeners = 42;
const e = new events.EventEmitter();
e.setMaxListeners(1);
e.on('uno', common.mustNotCall());
assert.ok(!e._events['uno'].hasOwnProperty('warned'));
e.on('uno', common.mustNotCall());
assert.ok(e._events['uno'].hasOwnProperty('warned'));

// chainable
assert.strictEqual(e, e.setMaxListeners(1));
// chainable
assert.strictEqual(e, e.setMaxListeners(1));
}

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