ADD unit tests, split and refactor source code

src/cli.js

@@ -0,0 +1,28 @@
+const actions = {
+  install: (callback) => require('./actions/install')(callback),
+  uninstall: (callback) => require('./actions/uninstall')(callback)
+};
+
+// Parse command line arguments and call the right action
+module.exports = ({ argv, exit }) => {
+  if (argv && argv.length > 2) {
+    const cmd = argv[2];
+
+    if (!actions[cmd]) {
+      console.log('Invalid command to go-npm. `install` and `uninstall` are the only supported commands');
+      exit(1);
+    } else {
+      actions[cmd]((err) => {
+        if (err) {
+          console.error(err);
+          exit(1);
+        } else {
+          exit(0);
+        }
+      });
+    }
+  } else {
+    console.log('Invalid command to go-npm. `install` and `uninstall` are the only supported commands');
+    exit(1);
+  }
+};