add: unit and integration testing

app/node_modules/strip-bom/index.d.ts

@@ -0,0 +1,14 @@
+/**
+Strip UTF-8 [byte order mark](https://en.wikipedia.org/wiki/Byte_order_mark#UTF-8) (BOM) from a string.
+
+@example
+```
+import stripBom = require('strip-bom');
+
+stripBom('\uFEFFunicorn');
+//=> 'unicorn'
+```
+*/
+declare function stripBom(string: string): string;
+
+export = stripBom;