Convert random generator to es6 and add some specs for it directly

test/key_generators/random_spec.js

@@ -0,0 +1,19 @@
+/* global describe, it */
+
+const assert = require('assert');
+
+const Generator = require('../../lib/key_generators/random');
+
+describe('RandomKeyGenerator', function() {
+  describe('randomKey', function() {
+    it('should return a key of the proper length', function() {
+      var gen = new Generator();
+      assert.equal(6, gen.createKey(6).length);
+    });
+
+    it('should use a key from the given keyset if given', () => {
+      var gen = new Generator({keyspace: 'A'});
+      assert.equal('AAAAAA', gen.createKey(6));
+    });
+  });
+});