Refactor valid UUID check into helpers

lib/actions/logs.coffee

@@ -1,15 +1,15 @@
 _ = require('lodash')
 PubNub = require('pubnub')
 resin = require('../resin')
+helpers = require('../helpers/helpers')
 
 LOGS_HISTORY_COUNT = 200
 
 exports.logs = (uuid) ->
-	resin.models.device.getAll (error, devices) ->
+	helpers.isDeviceUUIDValid uuid, (error, isValidUUID) ->
 		resin.errors.handle(error) if error?
 
-		uuidExists = _.findWhere(devices, { uuid })?
-		if not uuidExists
+		if not isValidUUID
 			return resin.errors.handle(new Error('Invalid UUID'))
 
 		# PubNub needs to be initialised after logs

lib/helpers/helpers.coffee

@@ -1,5 +1,14 @@
+_ = require('lodash')
+resin = require('../resin')
+
 exports.formatLongString = (string, n) ->
 	return string if not n?
 	splitRegexp = new RegExp(".{1,#{n}}", 'g')
 	splittedString = string.match(splitRegexp)
 	return splittedString.join('\n')
+
+exports.isDeviceUUIDValid = (uuid, callback) ->
+	resin.models.device.getAll (error, devices) ->
+		return callback?(error) if error?
+		uuidExists = _.findWhere(devices, { uuid })?
+		return callback(null, uuidExists)

lib/helpers/helpers.spec.coffee

@@ -1,6 +1,8 @@
 expect = require('chai').expect
+sinon = require('sinon')
 _ = require('lodash')
 helpers = require('./helpers')
+resin = require('../resin')
 
 STRING =
 	numbers: '1234567812345678'
@@ -33,3 +35,31 @@ describe 'Helpers:', ->
 			stringLength = STRING.numbers.length
 			result = helpers.formatLongString(STRING.numbers, stringLength + 1)
 			expect(result).to.equal(STRING.numbers)
+
+	describe '#isDeviceUUIDValid()', ->
+
+		devices = [
+			{ uuid: 1234 }
+			{ uuid: 5678 }
+		]
+
+		deviceGetAllStub = null
+
+		beforeEach ->
+			deviceGetAllStub = sinon.stub(resin.models.device, 'getAll')
+			deviceGetAllStub.yields(null, devices)
+
+		afterEach ->
+			deviceGetAllStub.restore()
+
+		it 'should return true if there is a device with that UUID', (done) ->
+			helpers.isDeviceUUIDValid devices[0].uuid, (error, isValid) ->
+				expect(error).to.not.exist
+				expect(isValid).to.be.true
+				done()
+
+		it 'should return false if there is not a device with that UUID', (done) ->
+			helpers.isDeviceUUIDValid 'invalidUUID', (error, isValid) ->
+				expect(error).to.not.exist
+				expect(isValid).to.be.false
+				done()