js: First testing and improvements

--

* Introduced Mocha/chai as testsuite. After development build
  'npm test' should run the unit tests. Functionality exclusive to
  Browsers/WebExtensions cannot be run this way, so some other testing
  is still needed.

  - package.json: Added required development packages
  - .babelrc indirect configuration for mocha. ES6 transpiling
    needs some babel configuration, but mocha has no setting for it.
  - test/mocha.opts Vonfiguration for mocha runs

* Fixed errors:
  - Helpers.js toKeyIdArray; isLongId is now exported
  - Key.js Key constructor failed
  - Message.js will not throw an Error during construction, a new
    message is now created with createMessage, which can return an
    Error or a GPGME_Message object

* Tests:
  - test/Helpers: exports from Helpers.js, GPGME_Error handling
  - test/Message: first init test with bad parameters

1 files changed, 1 insertions, 1 deletions

diff --git a/lang/js/src/Connection.js b/lang/js/src/Connection.js
index 5b092ab0..a10f9d9a 100644
--- a/lang/js/src/Connection.js
+++ b/lang/js/src/Connection.js
@@ -83,7 +83,7 @@ export class Connection{
      */
     post(message){
         if (!this.isConnected){
-            return Promise.reject(gpgme_error('CONN_NO_CONNECT'));
+            return Promise.reject(gpgme_error('CONN_DISCONNECTED'));
         }
         if (!message || !message instanceof GPGME_Message){
             return Promise.reject(gpgme_error('PARAM_WRONG'), message);