refactor: use explicit mocha imports (#497)

Author: JustinBeckwith

dialogflow/system-test/.eslintrc.yml

@@ -16,6 +16,7 @@
 
 const path = require('path');
 const {assert} = require('chai');
+const {describe, it} = require('mocha');
 const execSync = require('child_process').execSync;
 const cmd = 'node detect.js';
 const cmd_tts = 'node detect-intent-TTS-response.v2.js';

dialogflow/system-test/detect.test.js

@@ -15,6 +15,7 @@
 'use strict';
 
 const {assert} = require('chai');
+const {describe, it} = require('mocha');
 const {execSync} = require('child_process');
 const uuid = require('uuid/v4');
 

dialogflow/system-test/detect.v2beta1.test.js

@@ -15,6 +15,7 @@
 'use strict';
 
 const {assert} = require('chai');
+const {describe, it} = require('mocha');
 const execSync = require('child_process').execSync;
 const uuid = require('uuid');
 const exec = cmd => execSync(cmd, {encoding: 'utf8'});