add: unit and integration testing

app/node_modules/is-arrayish/index.js

@@ -0,0 +1,10 @@
+'use strict';
+
+module.exports = function isArrayish(obj) {
+	if (!obj) {
+		return false;
+	}
+
+	return obj instanceof Array || Array.isArray(obj) ||
+		(obj.length >= 0 && obj.splice instanceof Function);
+};