Improving CatanGraph Test Coverage and Catching a HashMap Overwrite Bug

TLDR

Improving test coverage for CatanGraph. Actually found a pretty nice bug! Overriding equals and hashCode of ResourceBundle so tests can do easy equality checks. Hitting all branches of conditional logic so Jacoco is happy.

Equals and Hash Code overrides.

@Override
public boolean equals(Object o) {
  if (this == o) {
    return true;
  }
  if (o instanceof ResourceBundle that) {
    return Objects.equals(resources, that.resources);
  } else {
    return false;
  }
}

@Override
public int hashCode() {
  return Objects.hash(
      ALL_RESOURCE_COLORS.stream().map(resources::get).toArray()
  );
}

Main work

• Used ChatGPT to generate tests for equals and hashCode for ResourceBundle
  • Also used it to debug issue with Objects.hash(...), it was not working as expected at first.
• Copying over test data from actual application running and writing assertions against it.
• Tracking down bug with overwritting hash map values.
• Thinking about how future tests will need to be added.
  • Mostly, creating the resources test folder containing board screenshots and JSON GameState dumps.

Challenges

• Difficulty debugging long functional Stream API expressions.
• Difficulty trying to quickly grok differences between Objects.hash(...) and Object.hashCode().
  • I’m sure I could dive into this and be 1000% sure about the differences, but I have a concert to go to. :D

Learnings

• Test Driven Design might have some merits!
  • Caught a bug where adjacent Road nodes for a Settlement were put() into the HashMap<GraphNode, List<GraphNode>> graph data structure, before being overwritten by a subsequent put() that adds the adjacent Hexagon nodes.