javascript - How Do I Test nested ES6 Generators using Mocha? -

i'm trying use co-mocha test nested generators functionality in koa app. class works fine @ runtime, when attempt test functionality, cannot nested generator run in test.

class being tested:

import promise 'bluebird'  class fooservice {   _doasync(){     return new promise((resolve) => {       settimeout(() => {         resolve({           foo: 'foo'         })       }, 500)     })   }    create(){     console.log('this never gets logged')     let self =     return function*(){       console.log(`this doesn't either`)       return yield self._doasync()     }   } } export default new fooservice() 

test file

import fooservice '../services/foo-service' import chai 'chai' let expect = chai.expect  describe('testing generators', () => {   it('should work', function *(){     console.log('this log never happens')     let result = yield fooservice.create()     expect(result).to.equal({foo: 'foo'})   }) }) 

i'm running mocha w/ --require co-mocha , node 4.2.6

while tests complete w/o errors, none of console above ever logged , i'm quite sure actual test generator never running @ all.

if try using npm package, mocha-generators instead, while log inside test generator, underlying generator returned create() method on service never fires...

what doing wrong??

without mocha-generators, it callback returns generator not run anyone. you'd need wrap in co manually mocha receive promise.

with mocha-generators, generator executed yields generator function. that's not expected, supposed yield promises. need call generator function create() call returns yourself, , shouldn't yield generator rather delegate via yield*:

let result = yield* fooservice.create()();