add: unit and integration testing

app/node_modules/strip-final-newline/index.js

@@ -0,0 +1,16 @@
+'use strict';
+
+module.exports = input => {
+	const LF = typeof input === 'string' ? '\n' : '\n'.charCodeAt();
+	const CR = typeof input === 'string' ? '\r' : '\r'.charCodeAt();
+
+	if (input[input.length - 1] === LF) {
+		input = input.slice(0, input.length - 1);
+	}
+
+	if (input[input.length - 1] === CR) {
+		input = input.slice(0, input.length - 1);
+	}
+
+	return input;
+};