tdd-calculator

Starter repo for http://osherove.com/tdd-kata-1/

Created with help from the jasmine examples generated from https://github.com/jasmine/jasmine-npm

Instructions

Fork, then clone this repo! Don't forget to cd into it =)

First make sure jasmine is installed. Let's install it globally (in this context, "global" refers to "this installation of node"). In your terminal, run:

npm install -g jasmine

In a moment, you'll see in spec/CalculatorSpec.js that I've set up some starter tests for you. You can run them all now, even before doing anything! All you have to do is run this command in your command line:

jasmine

Yes! It's that plain. Just the word jasmine with no arguments. You should see this output:

judytuna@ikran tdd-calculator (master) $ jasmine
Started
.F*

Failures:
1) Calculator Create a simple String calculator with a method add(numbers) should be able to return one single-digit integer
  Message:
    Expected 0 to equal 2.
  Stack:
    Error: Expected 0 to equal 2.
        at <Jasmine>
        at UserContext.<anonymous> (/Users/judytuna/techtonica/tdd-calculator/spec/CalculatorSpec.js:14:35)
        at <Jasmine>
Pending:

1) Calculator Create a simple String calculator with a method add(numbers) should add two numbers
  Temporarily disabled with xit

3 specs, 1 failure, 1 pending spec
Finished in 0.018 seconds

Now let's go back to looking at the code. Open it up in VS Code with code . (or your favorite editor). We only care about two files in this repo right now. Open up app/Calculator.js in one pane (let's say the left), and spec/CalculatorSpec.js in another pane (on the right). It really helps to see your code side-by-side with your tests.

I've written three tests in the spec file to get you started. I wrote a tiny bit of code in the app/Calculator.js file that makes the first test pass. That passing test shows up at the top as a green .. I've left the second test failing, so that you can see what the failure looks like (a red F). I've "x-ed out" the third test (which looks like a yellow *), so you focus on a single red (failing) test at a time. The rest of the functionality is up to you to implement!

In spec/CalculatorSpec.js, you can see that I've done the following things for you that you don't need to change:

• tell the spec file where to find the calculator code
• make a calculator variable that doesn't point to anything yet
• before every test, I create a new instance of my Calculator and set it to my calculator variable

This is the code for the passing test:

it("returns 0 if given an empty string", function() {
  expect(calculator.add("")).toEqual(0);
});

In this test code, I passed the string "" into calculator.add, and expected it to equal the integer 0.

How did I get this test to pass? In app/Calculator.js, you can see that I set up a Calculator function. It has just one function on its prototype called add that takes a single string as its only argument, and returns an integer. I made the above "empty string makes a 0" test pass by doing the easiest thing possible: it literally always returns zero! (You'll want to change that line and add functionality there later.) It makes the first test pass, but it's not going to work for any other cases =) That's why we need more tests!

Please follow the instructions in the TDD-kata link above and only work on one tiny thing at a time. First get the currently-failing "should be able to return one single-digit integer" test to pass. Then un-x the xited test on line 16 of the spec file, so that it starts with it instead of xit, and work on making that test pass.

Then you can move on to what the TDD-kata link says to work on next by adding more tests, one at a time, and making them pass, too!