add a callback optionnal parameter for server.close method (#528)

* add a callback optionnal parameter for server.close method

net and tls server.close method accept an optional callback parameter.
ldapjs server.close method delegates to net or tls server.close method and accept now an optional callback parameter...

* add tests for server.close callback

lib/server.js

@@ -732,8 +732,8 @@ Server.prototype.listenFD = function (fd) {
   this.port = fd;
   return this.server.listenFD(fd);
 };
-Server.prototype.close = function () {
-  return this.server.close();
+Server.prototype.close = function (callback) {
+  return this.server.close(callback);
 };
 Server.prototype.address = function () {
   return this.server.address();

test/server.test.js

@@ -310,4 +310,32 @@ test('non-strict routing', function (t) {
       });
     });
   });
+
+  test('close accept a callback', function (t) {
+    server = ldap.createServer();
+    // callback is called when the server is closed
+    server.close(function(err){
+      t.end();
+    });
+  });
+
+  test('close without error calls callback', function (t) {
+    server = ldap.createServer();
+    // when the server is closed without error, the callback parameter is undefined
+    server.listen(389,'127.0.0.1',function(err){
+      server.close(function(err){
+        t.error(err);
+        t.end();
+      });
+    });
+  });
+
+  test('close passes error to callback', function (t) {
+    server = ldap.createServer();
+    // when the server is closed with an error, the error is the first parameter of the callback
+    server.close(function(err){
+      t.ok(err);
+      t.end();
+    });
+  });
 });