Mocha tests fixed and enabled in travis config.

[koral--]

I've tried to add some tests related to #538 but realized that they are not executed on travis.
After fixing configs it turns out that one of your tests (keyutil parseKeyCharacterMap) is failing.

[lukzeg]

Hi @koral--

Mostly looks like we are trying to read not ready stream. I think we should add check:

diff --git a/lib/util/keyutil.js b/lib/util/keyutil.js
index cf494c9..9adf075 100644
--- a/lib/util/keyutil.js
+++ b/lib/util/keyutil.js
@@ -427,17 +427,20 @@ keyutil.parseKeyCharacterMap = function(stream) {
   }
 
   function readableListener() {
-    var chunk = stream.read()
-    var i = 0
-    var l = chunk.length
+    var chunk
 
-    try {
-      while (i < l) {
-        parse(String.fromCharCode(chunk[i++]))
+    while ((chunk = stream.read()) !== null) {
+      var i = 0
+      var l = chunk.length
+
+      try {
+        while (i < l) {
+          parse(String.fromCharCode(chunk[i++]))
+        }
+      }
+      catch (err) {
+        resolver.reject(err)
       }
-    }
-    catch (err) {
-      resolver.reject(err)
     }
   }

This change will fix the problem with

Uncaught TypeError: Cannot read property 'length' of null

error mentioned in :https://travis-ci.org/openstf/stf/jobs/201676025

Should I create separate PR with fix for it?

I double checked the changes and I did not observed any issues on live running STF.

Fix base on comment:
https://stackoverflow.com/questions/21549161/readable-event-occurs-twice/22751069