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 <[email protected]>
Change-Id: Idf809cb08d8c1ef177ff92f0ee1be04ac74059a3

Author: Sukanya Pandey

.eslintrc.js

@@ -18,14 +18,18 @@ module.exports = {
   parserOptions: {
     parser: 'babel-eslint'
   },
+  globals: {
+    expect: true,
+    sinon: true
+  },
   overrides: [
     {
       files: [
         '**/__tests__/*.{j,t}s?(x)',
         '**/tests/unit/**/*.spec.{j,t}s?(x)'
       ],
       env: {
-        jest: true
+        mocha: true
       }
     }
   ]