PromisePool to always use the specified promises library

Author: nasplachkov

promise.js

@@ -356,15 +356,15 @@ PromisePool.prototype.execute = function(sql, values) {
   var corePool = this.pool;
   const localErr = new Error();
 
-  return new Promise(function(resolve, reject) {
+  return new this.Promise(function(resolve, reject) {
     corePool.execute(sql, values, makeDoneCb(resolve, reject, localErr));
   });
 };
 
 PromisePool.prototype.end = function() {
   var corePool = this.pool;
   const localErr = new Error();
-  return new Promise(function(resolve, reject) {
+  return new this.Promise(function(resolve, reject) {
     corePool.end(function(err) {
       if (err) {
         localErr.message = err.message;

test/integration/promise-wrappers/test-promise-wrappers.js

@@ -307,6 +307,24 @@ function testObjParamsPool() {
       console.log(err);
     });
 }
+function testPromiseLibrary() {
+  var pool = createPool(config);
+  var promise = pool.execute({
+	  sql: 'select ?-? as ttt',
+	  values: [8, 5]
+  });
+  promise
+    .then(function() {
+      assert.ok(promise instanceof pool.Promise);
+    })
+    .then(function() {
+      promise = pool.end();
+      assert.ok(promise instanceof pool.Promise);
+    })
+    .catch(function(err) {
+        console.log(err);
+    });
+}
 
 function testEventsPool() {
   var pool = createPool(config);
@@ -470,6 +488,7 @@ testObjParamsPool();
 testEventsPool();
 testChangeUser();
 testPoolConnectionDestroy();
+testPromiseLibrary();
 
 process.on('exit', function() {
   if (skipTest) {