add simple tests.
1. `test1.js` requires another file in 3 different ways.
	test1_exports.js: exports = return_value;
	test1_module_exports.js: module.exports=return_value;
	test1_return.js: return return_value;
    `test1.js` uses 'VOBA_PATH' to find the javascript.
2. `test2.js` is similar to `test1`, but use relative directory to find the javascript file.