before/after have wrong "this" scope?

[zzen]

beforeEach/afterEach correctly invoke with "this" set to the scope of the suite. before/after however use global object instead. Maybe I'm missing something, but it seems weird why this would be intentional.

Test case:

assert = require('assert')

describe('scope is lost',function() {
    before(function() { this.foo="world"}) // also this leaks into global scope
    describe('when using before/after', function() {
        it('should have value set for foo', function() { assert.equal(this.foo,'world') })
    })
})

describe('scope works fine',function() {
    beforeEach(function() { this.bar="hello"})
    describe('when using beforeEach/afterEach', function() {
        it('should have value set for bar', function() { assert.equal(this.bar,'hello') })
    })
})

Result:

scope is lost
  0) "before all" hook
  when using before/after
    1) should have value set for foo

scope works fine
  when using beforeEach/afterEach
    ✓ should have value set for bar 


✖ 2 of 2 tests failed:

0) scope is lost "before all" hook:
   Error: global leak detected: foo
    at Runner.checkGlobals (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:103:21)
    at Runner.<anonymous> (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:44:44)
    at Runner.emit (events.js:64:17)
    at /Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:170:12
    at Hook.run (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runnable.js:155:5)
    at next (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:167:10)
    at Array.<anonymous> (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:177:5)
    at EventEmitter._tickCallback (node.js:126:26)

1) scope is lost when using before/after should have value set for foo:

ssertionError: "world" == "undefined"
    at Test.fn (/Users/jakub/Documents/test.js:6:59)
    at Test.run (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runnable.js:153:32)
    at Runner.runTest (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:272:10)
    at /Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:313:12
    at next (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:200:14)
    at /Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:209:7
    at next (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:157:23)
    at Array.<anonymous> (/Users/jakub/.nvm/v0.4.12/lib/node_modules/mocha/lib/runner.js:177:5)
    at EventEmitter._tickCallback (node.js:126:26)

[tj]

beforeEach/afterEach use "this" as the Test, which doesn't make sense for before/after, since it's all serial we could use Suite, or a custom Context object would be better since then we could delegate this.timeout(n) -> this.test.timeout(n)

[zzen]

Maybe I'm doing this wrong then. I'm trying to get a setup into place, then run a bunch of tests and have a teardown. Pretty common use-case, right? Part of my setup is a creating a tobi browser instanceI want to reuse in the tests. But how do I push that instance into the tests (without having it in beforeEach)?

[tj]

well you can do the same thing with closures:

describe('something', function(){
  var foo;

   ...before...
     foo = stuff
   ..

blah blah haha which is also helpful for:

describe('utils.parseCookie()', function(){
  var parse = utils.parseCookie;

  it('should do something', function(){
    parse(foo)
  })

  it('should do something', function(){
    parse(foo)
  })

  it('should do something', function(){
    parse(foo)
  })
})

but this sort of thing would be nice for shared behaviours since they're not lexically scoped

[zzen]

True, somehow that escaped me, late night :) Thanks.
Going back to topic - anything sounds better then running before/after in global context.

[zzen]

Right - that's why I didn't originally click with closures: I got async tests that need async setup...

describe('Async tests', function(){
    before(function(done) {
      initDb(function(err, conn) {
            this.connection = conn;
            done()
        })
    })

    describe('Query Database', function() {
        before(function(done) {
            this.conn.query('select something', done)
        })
        it('should return results', function(data) {
            assert ...
        })
    })

[tj]

well you can still use enclosed vars for that:

describe('something', function(){
  var connection;
  before(function(done){
    initwhatever(function(err, conn){
      connection = conn;
      done();
      ...
  })

^ is effectively identical

[tj]

https://github.com/visionmedia/mocha/wiki/Shared-Behaviours is the only reason we need "this" as anything special

[zzen]

Thanks TJ

[fernandoPalaciosGit]

Thanks, the only way is reference by the chain testing, it -> it -> it, thats not preaty nice

this.test.parent.parent

[fernandoPalaciosGit]

Maybe creating a simple Object for the main ñcontext testing

var Test = {
    connection: null
};

beforeEach(function () {
    this.connection = new MongoDbConn();
}.bind(Test));

describe('something', function(){
    it('do a query', function(done){
        initwhatever(function(err, conn){
            this.connection.query('select something', done);
            done();
        }.bind(Test));
    });
});

A simple Restfull API testing

[boneskull]

My recommendation is to use closures instead of assigning things to this.