Game Engine Tests

[Code-Over-Time]

Category: General Development

Level: Mid

Description

Many of the projects within Code Over Time have a test suite that can be executed to verify that the product is functional, but there is one significant gap in the test coverage.

The Rock, Paper, Scissors Apocalypse game engine has no tests at all, despite being quite testable.

If you open game_rps/game_engine you will find a folder called tests... but sadly it is empty. This is an all too common occurrence. We start out with the best of intentions - planning to implement a whole bunch of tests, but it's kind of boring so we put if off, and never get back to it.

For this task you need to write some functional tests (end to end functionality) and unit tests (testing small units of work).

For example, you should test that you can play an entire game using this engine. That the game ends successfully and only one person wins. That is your functional test.

Then you should test individual bits of logic, like:

class Rock extends Weapon {
  get id () {
    return 'rock'
  }

  getAttackResult (vs) {
    if (vs instanceof Paper) {
      return Weapon.LOSE
    }
    if (vs instanceof Scissors) {
      return Weapon.WIN
    }
    return super.getAttackResult(vs)
  }
}

Here it should be pretty simple to verify the behavior of the Rock in our Rock, Paper, Scissors game.

You don't need to get 100% coverage here, just use your judgement to make sure you are testing the most important parts of the game (like the above weapon test - it's critical that this works as expected).

Deliverable

• A functional test that verifies end to end functionality of the game engine
• A suite of unit tests to verify core game logic

Acceptance Criteria

• Automated tests verify that a game can be played in its entirety (functional test)
• Logic within individual models is unit tested

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Task Tips!

• Remember to test failure scenarios - don't just test the happy path where everything just works. What happens if you use invalid arguments to functions, like a string instead of a number? What if you try to start a game with only one player added? You need to verify that things fail gracefully
• Start with src/game_models.js as it should be easy to write tests for
• Check out the client code to see how it creates and runs a game - your test will have to do something similar
• You can use whatever Javascript testing tools you like. Jest, for example, is a popular choice