Saturday, August 24, 2019

The Importance of Testing

Before you write any code you should have a way in your mind to test the code in order to make sure that the code does what you want. There are many types of tests but when you get right down to it, all tests are either manual or automated. Manual tests tend to be the easiest to implement as they just require some code that can be observed to be doing the correct thing. As games tend to be dynamic in nature, manual testing is very common in game development as coming up with automated tests is not always practical. Automated tests, however, are always preferable when possible to do so due to the simple fact that people do not have the time to go through hours of manual testing just to make a minor change. This means that most manual tests will only be run on rare occasions so that something may be broken for months before it is discovered making finding out why it broke difficult.

Due to the visual nature of the cards, automatic testing is not really that practical so we will resort to manual testing. More to the point, as the cards are poignant to the game, any problems with the card class will be detected immediately so manually testing them is not much of a risk. A very simple test program can be created to make sure that the card class works the way it is supposed to.

Create a new “CardTest” movie for holding the test. Copy the Card movie clip into this movie. This can be done by having a file with that movie open in another tab then in the library tab selecting that file and dragging the Card movie onto the stage. Make sure that the layer holding the card extends to the second frame. Add a layer for holding code and in the second frame create a blank keyframe in the code layer. Right-click and chose add actions to bring up the code editor for editing JavaScript on that frame. Here is the test code:

var firstCard = new spelchan.Card(this.firstCardMovie);
this.firstCardMovie.addEventListener("click", nextCard);

function nextCard(e) {
if (firstCard.faceShowing)
firstCard.setCard(firstCard.cardID + 1);
console.log("face: " + firstCard.getFaceValue() +
" suit: " + firstCard.getSuit());

While in the actions editor, make sure to add the Deck.js file to the includes by expanding the global list of scripts then selecting the include option and clicking on the + to add a script. Browse to find the script.

You can now simply click on the card to show the first card in the deck and keep clicking on the cards to loop through all the cards that make up a deck. This is a very simple test but one that confirms that the Card class is working as expected. Proponents of the technique known as test driven development would start with the test code and then write the actual code as we will see when creating the deck class that deals with handling a deck of cards.

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