JUnit Tests with Processing in Eclipse

Processing
1

I’m trying to get JUnit tests working with Processing but I’m not sure how to go about it. Every way I’ve tried either ends up with a ClassNotFoundException, or says size() cannot be used here (when I use Main app = new Main() followed by app.settings())
Is there a way to get this working?

2

What exactly are you trying to test?

3

I’m trying to test wall collisions in a game I’m making

4

It’s not exactly trivial to write unit tests for Processing (or for user interfaces in general).

If you really want to write a unit test for your code, here’s what I would do:

  • Extract your logic into separate classes that don’t care about rendering. For example, your collision detection shouldn’t have to care about your rendering code.
  • Write unit tests for those separate classes.
  • Optionally, to test the user interface, consider outputting your sketch as a series of screenshots and comparing the screenshots to each other.

For example, maybe you’d have a class like this:

public class CollisionChecker{
  public boolean checkCollision(Rectangle one, Rectangle two){
    // check collisions here
  }
}

Then in your Processing sketch, you could do something like this:

void draw(){
  if(collisionChecker.checkCollision(playerRectangle, enemyRectangle){
    gameOver();
  }

  playerRectangle.draw();
  enemyRectangle.draw();
}

Then you could write unit tests for CollisionChecker without worrying about any rendering code.

5

Thanks, that’s going to take a fair bit of work for what I’m doing but it should work

6

Out of curiosity, what context are you coming from where you want to write unit tests for Processing? Most people who write in Processing would just skip the unit tests. :wink:

7

There’s a lot of maths involved in what I’m doing and a great possibility that when I add something that it could stuff up code elsewhere and I wouldn’t know where to start looking to find the problem. This way with the JUnit tests, if I break something I thought was working I’ll be notified so I can avoid trying to search through walls of code for an error that originated elsewhere. (I’m also having trouble finding the solution the error I have currently with just the help of the debugger)

8

Does Java provides a JUinit/assertion library? @Kevin

Kf

9

Yeah, JUnit is a Java library that you use to do unit testing. (I have a tutorial on this ready to go, I just haven’t posted it yet.)