Rewrite concurrent prepaid test

This test has been unstable, possibly because it was using one request instance to fire off
requests for many users. Rewrote using generators and multiple request instances with
separate cookie jars. For #3469.

spec/server/functional/prepaid.spec.coffee

@@ -4,6 +4,8 @@ moment = require 'moment'
 {findStripeSubscription} = require '../../../server/lib/utils'
 async = require 'async'
 nockUtils = require '../nock-utils'
+utils = require '../utils'
+Promise = require 'bluebird'
 
 describe '/db/prepaid', ->
   prepaidURL = getURL('/db/prepaid')
@@ -726,49 +728,50 @@ describe '/db/prepaid', ->
           expect(res.statusCode).not.toEqual(200)
           done()
 
-    xit 'Test a bunch of people trying to redeem at once', (done) ->
-      nockUtils.setupNock 'db-sub-redeem-test-3.json', (err, nockDone) ->
-        doRedeem = (userX, code, testnum, retry, fnDone) =>
-          loginUser userX, () =>
-            endDate = new moment().add(3, 'months').toISOString().substring(0, 10)
-            subscribeWithPrepaid code, (err, res, result) ->
-              if err
-                return fnDone(err)
-  
-              expect(err).toBeNull()
-              expect(result).toBeDefined()
-              if result.stripe
-                expect(result.stripe).toBeDefined()
-                expect(result.stripe.free).toEqual(endDate)
-                expect(result?.purchased?.gems).toEqual(10500)
-                return fnDone(null, {status: "ok", msg: "Redeemed " + retry})
-              else
-                return fnDone(null, {status: 'error', msg: "Redeem attempt Error #{result} (#{userX.id})" + retry })
+    it 'enforces the maximum number of redeemers in a race condition', utils.wrap (done) ->
+      nockDone = yield nockUtils.setupNockAsync 'db-sub-redeem-test-3.json'
+      stripe.tokens.createAsync = Promise.promisify(stripe.tokens.create, {context: stripe.tokens})
+      token = yield stripe.tokens.createAsync({
+        card: { number: '4242424242424242', exp_month: 12, exp_year: 2020, cvc: '123' }
+      })
 
-        redeemPrepaidFn = (code, testnum) =>
-          (fnDone) =>
-            loginNewUser (user1) =>
-              doRedeem(user1, code, testnum, 0, fnDone)
+      user = yield utils.initUser()
+      yield utils.loginUser(user)
+      
+      codeRedeemers = 50
+      codeMonths = 3
+      redeemers = 51
+      
+      purchasePrepaidAsync = Promise.promisify(purchasePrepaid, {multiArgs: true})
+      [res, prepaid] = yield purchasePrepaidAsync('terminal_subscription', months: codeMonths, codeRedeemers, token.id)
+      
+      expect(prepaid).toBeDefined()
+      expect(prepaid.code).toBeDefined()
 
-        stripe.tokens.create {
-          card: { number: '4242424242424242', exp_month: 12, exp_year: 2020, cvc: '123' }
-        }, (err, token) ->
-          loginNewUser (user) =>
-            codeRedeemers = 50
-            codeMonths = 3
-            redeemers = 51
-            purchasePrepaid 'terminal_subscription', months: codeMonths, codeRedeemers, token.id, (err, res, prepaid) ->
-              expect(err).toBeNull()
-              expect(prepaid).toBeDefined()
-              expect(prepaid.code).toBeDefined()
-              tasks = (redeemPrepaidFn(prepaid.code, i) for i in [0...redeemers])
-              async.parallel tasks, (err, results) =>
-                redeemed = 0
-                error = 0
-                for result in results
-                  redeemed += 1 if result.status is 'ok'
-                  error += 1 if result.status is 'error'
-                expect(redeemed).toEqual(codeRedeemers)
-                expect(error).toEqual(redeemers - codeRedeemers)
-                nockDone()
-                done()
+      # Make 'threads', which are objects that encapsulate each user and their cookies
+      threads = []
+      for index in [0...redeemers]
+        thread = {}
+        thread.request = request.defaults({jar: request.jar()})
+        thread.request.postAsync = Promise.promisify(thread.request.post, { context: thread.request })
+        thread.user = yield utils.initUser()
+        yield utils.loginUser(thread.user, {request: thread.request})
+        threads.push(thread)
+    
+      # Spawn all requests at once!
+      requests = []
+      options = { 
+        url: getURL('/db/subscription/-/subscribe_prepaid')
+        json: { ppc: prepaid.code }
+      }
+      for thread in threads
+        requests.push(thread.request.postAsync(options))
+        
+      # Wait until all requests finish, make sure all but one succeeded 
+      responses = yield requests
+      redeemed = _.size(_.where(responses, {statusCode: 200}))
+      errors = _.size(_.where(responses, {statusCode: 403}))
+      expect(redeemed).toEqual(codeRedeemers)
+      expect(errors).toEqual(redeemers - codeRedeemers)
+      nockDone()
+      done()

spec/server/nock-utils.coffee

@@ -1,6 +1,7 @@
 nock = require('nock')
 nockBack = nock.back
 nockBack.fixtures = 'spec/fixtures/'
+Promise = require 'bluebird'
 
 module.exports.setupNock = (fixtureFilename, options, done) ->
   if _.isFunction(options)
@@ -76,3 +77,4 @@ module.exports.teardownNock = ->
 before = (scope) ->
   scope.body = (body) -> true
   
+Promise.promisifyAll(module.exports)

spec/server/utils.coffee

@@ -29,12 +29,15 @@ module.exports = mw =
     promise = user.save()
     return promise
 
-  loginUser: Promise.promisify  (user, done) ->
+  loginUser: Promise.promisify  (user, options={}, done) ->
+    if _.isFunction(options)
+      done = options
+      options = {}
     form = {
       username: user.get('email')
       password: 'password'
     }
-    request.post mw.getURL('/auth/login'), { form: form }, (err, res) ->
+    (options.request or request).post mw.getURL('/auth/login'), { form: form }, (err, res) ->
       expect(err).toBe(null)
       expect(res.statusCode).toBe(200)
       done(err, user)