Remove callback API from Genrator#github.username() in favor of Promi…

…se one - ref #1006

lib/actions/user.js

@@ -17,6 +17,7 @@ user.github = {};
 /**
  * Retrieves user's name from Git in the global scope or the project scope
  * (it'll take what Git will use in the current context)
+ * @return {String} configured git name or undefined
  */
 user.git.name = () => {
   let name = nameCache.get(process.cwd());
@@ -36,6 +37,7 @@ user.git.name = () => {
 /**
  * Retrieves user's email from Git in the global scope or the project scope
  * (it'll take what Git will use in the current context)
+ * @return {String} configured git email or undefined
  */
 user.git.email = () => {
   let email = emailCache.get(process.cwd());
@@ -54,16 +56,9 @@ user.git.email = () => {
 
 /**
  * Retrieves GitHub's username from the GitHub API
+ * @return {Promise} Resolved with the github username or rejected if unable to
+ *                   get the information
  */
-user.github.username = cb => {
-  const promise = githubUsername(user.git.email());
-
-  if (cb) {
-    promise.then(
-      val => cb(null, val),
-      err => cb(err)
-    );
-  }
-
-  return promise;
+user.github.username = () => {
+  return githubUsername(user.git.email());
 };

test/user.js

@@ -104,10 +104,9 @@ describe('Base#user', () => {
         nock.restore();
       });
 
-      it('is the username used by GitHub', function (done) {
-        this.user.github.username((_, res) => {
+      it('is the username used by GitHub', function () {
+        return this.user.github.username().then(res => {
           assert.equal(res, 'mockname');
-          done();
         });
       });
     });