Google Apps Script - Find from right

I am getting familiar with Google Spreadsheets and Google Apps Script.

For a sheet used for expense tracking I needed a findFromRight function in Google Apps Script.

I let myself be inspired from the Excel VBA world and found something from Chris Rae's site that could be modified:

	// inspired by Chris Rae's VBA site: http://chrisrae.com/vba/
	function findRight(findIn, findWhat) {
	var findLoc=0;
	for(findLoc=(findIn.length - findWhat.length + 1);findLoc>=1;findLoc--)
	{
	if (findIn.substring(findLoc,(findLoc + findWhat.length)) === findWhat) {return findLoc;}
	}
	return -1;
	}

view raw findFromRight.js hosted with ❤ by GitHub

To add testing to this Google Apps Script, I decided to try out the GAS-Unit testing framework.

	var q = 'http://gas-unit.googlecode.com/svn/trunk/gas-unit/gasUnit.js';
	var s = UrlFetchApp.fetch(q).getContentText();
	eval(s);
	function runFindRightAssertions() {
	var testFixture = new TestFixture('Tests on findRight function');
	testFixture.addTest(
	"third space character in string returns 2",
	function () {
	this.assertAreEqual(2,findRight("VB ", " "));
	});
	testFixture.addTest(
	"not containing character returns -1",
	function () {
	this.assertAreEqual(-1,findRight("VB ", "A"));
	});
	testFixture.addTest(
	"searching empty string returns -1",
	function () {
	this.assertAreEqual(-1,findRight("", "A"));
	});
	testFixture.addTest(
	"flipped order search returns -1",
	function () {
	this.assertAreEqual(-1,findRight("BA", "AB"));
	});
	testFixture.addTest(
	"searching partially matched string returns -1",
	function () {
	this.assertAreEqual(-1,findRight("BAQ", "BAQH"));
	});
	testFixture.addTest(
	"complete match returns 0",
	function () {
	this.assertAreEqual(-1,findRight("BAQH", "BAQH"));
	});
	var retVal = testFixture.runTests().getResultsSummary();
	Logger.log(testFixture.createTextTestReport());
	//MailApp.sendEmail("myname@example.com", "test report", Logger.getLog(), {htmlBody: testFixture.runTests().createHtmlTestReport() });
	return retVal;
	}

view raw FindRightTests.js hosted with ❤ by GitHub

There are two ways to view the test results. The code above only prints to the log view (View-> Logs in the menus). It is also possible to receive the test result as a formatted report per mail (by including the outcommented line and updating the email address).

All in all, I find that using the testing framework can be of good help to establish that the functions are working as expected (and keep working as expected when redesigned).