Should tearDown be queued on process.nextTick?

I've encountered an issue that's reproducible with async.parallel/auto and nodeunit.

``` javascript
var async = require('async');
var str;

exports.setUp = function(cb){
console.log('setup');
str = "This is a test";
cb();
}

exports.tearDown = function(cb){
//process.nextTick(function(){
console.log('teardown');
str = undefined;
cb();
//});
}

exports["testA"] = function(test){
async.auto({
test1:function(cb, results){
console.log('test1');
cb(new Error("test"));
},
test2:function(cb, results){
console.log('test2');
console.log(str, str.length);
cb();
}
}, function(err, results){
if(err) console.error(err);
test.done();
});
}

exports["testB"] = function(test){
async.parallel({
test1:function(cb, results){
console.log('test1');
cb(new Error("test"));
},
test2:function(cb, results){
console.log('test2');
console.log(str, str.length);
cb();
}
}, function(err, results){
if(err) console.error(err);
test.done();
});
}
```

This produces the output:

> setup
> test1
> [Error: test]
> teardown
> test2
> teardown
> ✖ testA
>
> TypeError: Cannot read property 'length' of undefined
> at Array.exports.testA.async.auto.test2 [as 0](/Users/davefenster/temp/testnodeunitbug/test.js:26:24)
> at async.auto (/Users/davefenster/node_modules/async/lib/async.js:406:38)
> at Array.forEach (native)
> at _forEach (/Users/davefenster/node_modules/async/lib/async.js:26:24)
> at Object.async.auto (/Users/davefenster/node_modules/async/lib/async.js:382:9)
> at Object.exports.testA (/Users/davefenster/temp/testnodeunitbug/test.js:19:8)
> at wrapTest (/Users/davefenster/node_modules/nodeunit/lib/core.js:231:20)
> at _asyncMap (/Users/davefenster/node_modules/nodeunit/deps/async.js:163:13)
> at async.forEachSeries.iterate (/Users/davefenster/node_modules/nodeunit/deps/async.js:126:25)
> at _asyncMap (/Users/davefenster/node_modules/nodeunit/deps/async.js:160:17)
>
> setup
> test1
> [Error: test]
> teardown
> test2
> teardown
> ✖ testA
>
> TypeError: Cannot read property 'length' of undefined
> at Array.exports.testA.async.auto.test2 [as 0](/Users/davefenster/temp/testnodeunitbug/test.js:26:24)
> at async.auto (/Users/davefenster/node_modules/async/lib/async.js:406:38)
> at Array.forEach (native)
> at _forEach (/Users/davefenster/node_modules/async/lib/async.js:26:24)
> at Object.async.auto (/Users/davefenster/node_modules/async/lib/async.js:382:9)
> at Object.exports.testA (/Users/davefenster/temp/testnodeunitbug/test.js:19:8)
> at wrapTest (/Users/davefenster/node_modules/nodeunit/lib/core.js:231:20)
> at _asyncMap (/Users/davefenster/node_modules/nodeunit/deps/async.js:163:13)
> at async.forEachSeries.iterate (/Users/davefenster/node_modules/nodeunit/deps/async.js:126:25)
> at _asyncMap (/Users/davefenster/node_modules/nodeunit/deps/async.js:160:17)
>
> FAILURES: 2/2 assertions failed (12ms)
>
> FAILURES: Undone tests (or their setups/teardowns):
> - testB
>
> To fix this, make sure all tests call test.done()

The error manifests itself because tearDown runs before all the async.auto and async.parallel functions have executed. Ideally, what I'd want is the tearDown to run only after async.auto/parallel are complete.
To make the tests pass, uncomment the process.nextTick line in the tearDown function.

Should nodeunit be putting tearDown on the nextTick queue all the time?

Tái hiện vấn đề với các fixture async.auto và async.parallel được nêu trong báo cáo, sau đó kiểm tra nodeunit/lib/core.js quanh wrapTest và cách xử lý teardown của nó. Xác minh thứ tự của tearDown so với các callback bất đồng bộ, đồng thời xác nhận rằng các bài kiểm thử đã hoàn thành không còn truy cập trạng thái đã được dọn dẹp trước khi tearDown hoàn tất.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.