jasts

jasts - Jasmine TypeScript classes for better unit testing

Jasmine is a really good testing tool for JavaScript.   It's well known, well documented, widely used, and has personally helped me catch a lot of bugs before they've seen the light of day. Thank you to the Jasmine team for making a really good tool.

Jasmine has two areas where it can help developers better, and this project fills in those two gaps.

Gap 1: Error messages when a test fails.

it ("Test emptying the shopping cart", function () {
  const cart:ShoppingCart = new ShoppingCart();
  cart.put (product1);
  cart.put (product2);
  cart.clear ();
  expect (cart.numberOfItemsInCart ()).toEqual(0);
  expect (cart.calculatePrice ()).toEqual(0);
});

And then you get back the helpful error message: Expected undefined to equal 0.

This error message doesn't tell you which line brought back the wrong result.
Do I have a bug with the first call or the second call?

Gap 2: Expect syntax is unusual

The expect (something()).method(somethingElse()) syntax is criticized for being unusual (although it does open up a great deal of flexibility).

Solution: npm i jasts --save-dev

it ("Test emptying the shopping cart", function () {
  const cart:ShoppingCart = new ShoppingCart();
  cart.put (product1);
  cart.put (product2);
  cart.clear ();
  TestNumber.equals ("no items in cart", cart.numberOfItemsInCart (), 0);
  TestNumber.equals ("empty cart should cost nothing", cart.calculatePrice (), 0);
});

Returns the far better error message: Failed: empty cart should cost nothing - value was undefined expected 0

Because you can provide text with each failure message, knowing exactly which statement failed with the chance for the developer to provide intelligent comments makes for quicker and easier debugging.

What classes does Jasts provide?

TestBoolean
	true	TestBoolean.true ("Test failure message if this boolean isnt true", dataToTest);
	false	TestBoolean.false ("Test failure message if this boolean isnt false", dataToTest);
	equals	TestBoolean.equals ("Test failure message if these booleans arent equal", dataToTest, dataToTestAgainst);
	null	TestBoolean.null ("Test failure message if this boolean isnt null", dataToTest);
	undefined	TestBoolean.undefined ("Test failure message if this boolean isnt undefined", dataToTest);
	notNull	TestBoolean.notNull ("Test failure message if this boolean is null", dataToTest);
	notUndefined	TestBoolean.notUndefined ("Test failure message if this boolean is undefined", dataToTest);
	notNullOrUndefined	TestBoolean.notNullOrUndefined ("Test failure message if this boolean is null or undefined", dataToTest);

TestNumber
	equals	TestNumber.equals ("Test failure message if these numbers arent equal", dataToTest, numberItHasToEqual);
	greaterThan	TestNumber.greaterThan ("Test failure message if dataToTest is not greater than numberItHasToBeGreaterThan", dataToTest, numberItHasToBeGreaterThan);
	lessThan	TestNumber.lessThan ("Test failure message if dataToTest is not greater than numberItHasToBeLessThan", dataToTest, numberItHasToBeLessThan);
	undefined	TestNumber.undefined ("Test failure message if this number isnt undefined", dataToTest);
	null	TestNumber.null ("Test failure message if this number isnt null", dataToTest);
	notEquals	TestNumber.notEquals ("Test failure message if these numbers are equal", dataToTest, numberItHasToEqual);
	notNullOrUndefined	TestNumber.notNullOrUndefined ("Test failure message if this number is null or undefined", dataToTest);
	notUndefined	TestNumber.notUndefined ("Test failure message if this number is undefined", dataToTest);
	notNull	TestNumber.notNull ("Test failure message if this number is null", dataToTest);

TestString
	equals	TestString.equals ("Test failure message if these strings arent equal", dataToTest, stringItHasToEqual);
	null	TestString.null ("Test failure message if this string is not null", dataToTest);
	undefined	TestString.undefined ("Test failure message if this string is not undefined", dataToTest);
	notNull	TestString.notNull ("Test failure message if this string is null", dataToTest);
	notUndefined	TestString.notUndefined ("Test failure message if this string is undefined", dataToTest);
	notNullOrUndefined	TestString.notUndefined ("Test failure message if this string is null or undefined", dataToTest);

Test
	equals	Test.equals ("Test failure message if these objects arent equal", dataToTest, stringItHasToEqual);
	null	Test.null ("Test failure message if this object is not null", dataToTest);
	undefined	Test.undefined ("Test failure message if this object is not undefined", dataToTest);
	notNull	Test.notNull ("Test failure message if this object is null", dataToTest);
	notUndefined	Test.notUndefined ("Test failure message if this object is undefined", dataToTest);
	notNullOrUndefined	Test.notNullOrUndefined ("Test failure message if this object is null or undefined", dataToTest);