Add mocha and chai test framework

  - Mocha/Chai/Sinon test frameowrk because it has 100% feature parity with vue-loader.
  - Code for making 'expect' function accessible globally.

Signed-off-by: Sukanya Pandey <sukapan1@in.ibm.com>
Change-Id: Idf809cb08d8c1ef177ff92f0ee1be04ac74059a3
diff --git a/.eslintrc.js b/.eslintrc.js
index b28fdf4..d0344ab 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -18,6 +18,10 @@
   parserOptions: {
     parser: 'babel-eslint'
   },
+  globals: {
+    expect: true,
+    sinon: true
+  },
   overrides: [
     {
       files: [
@@ -25,7 +29,7 @@
         '**/tests/unit/**/*.spec.{j,t}s?(x)'
       ],
       env: {
-        jest: true
+        mocha: true
       }
     }
   ]