Testing & Debugging Guide

Testing and debugging are essential parts of bot development. This guide covers strategies for testing your bot's behavior, diagnosing issues, and improving performance through systematic testing.

Testing Strategies

Local Testing Workflow

A typical bot testing workflow includes:

1. Unit testing - Test individual algorithms in isolation
2. Integration testing - Test bot behavior in battles
3. Performance testing - Measure win rates against reference bots
4. Regression testing - Ensure changes don't break existing behavior

Choosing Test Opponents

Select appropriate opponents for different testing phases:

Static targets (sample bots):

• Target - Doesn't move, useful for testing targeting accuracy
• Walls - Moves along walls, tests wall avoidance
• Corners - Stays in corners, tests corner targeting

Reference bots:

• Test against known-strength bots to measure improvement
• Use consistent opponent set for comparable results
• Include both strong and weak opponents in your suite

Specialized opponents:

• Rammers - Test collision avoidance
• Pattern movers - Test adaptive targeting
• Strong dodgers - Test targeting accuracy against evasive bots

Battle Configuration for Testing

Use consistent battle settings:

{
  "numberOfRounds": 35,
  "arenaWidth": 800,
  "arenaHeight": 600,
  "turnTimeout": 30000
}

Why 35 rounds? Multiple rounds reduce variance and provide statistically meaningful results.

See Custom Game Setup for battle configuration details.

Debugging Techniques

Print Debugging

The simplest debugging technique is printing to console:

Java:

System.out.println("Debug: currentHeading=" + getDirection());

Python:

print(f"Debug: currentHeading={self.direction}")

C#:

Console.WriteLine($"Debug: currentHeading={Direction}");

TypeScript:

console.log(`Debug: currentHeading=${this.getDirection()}`);

Conditional Debug Output

Avoid excessive logging by using debug flags:

private static final boolean DEBUG = true;

private void debug(String message) {
    if (DEBUG) {
        System.out.println(message);
    }
}

Visualizing Bot State

Print key variables at decision points:

• Current position and heading
• Target enemy position
• Calculated angles and distances
• Decision variables (which algorithm is active, etc.)

Server Debug Mode

Run the server with debug logging enabled:

robocode-tankroyale-server --debug

This shows:

• Bot registration and communication
• Server-side events
• Network protocol details

See Debugging for complete debugging options.

Performance Profiling

Measuring Execution Time

Track algorithm execution time to avoid timeout penalties:

Java:

long startTime = System.nanoTime();
// Your algorithm here
long duration = System.nanoTime() - startTime;
System.out.println("Algorithm took: " + duration + " ns");

Python:

import time
start_time = time.perf_counter()
# Your algorithm here
duration = time.perf_counter() - start_time
print(f"Algorithm took: {duration*1000:.3f} ms")

C#:

var startTime = System.Diagnostics.Stopwatch.GetTimestamp();
// Your algorithm here
var duration = System.Diagnostics.Stopwatch.GetElapsedTime(startTime);
Console.WriteLine($"Algorithm took: {duration.TotalMilliseconds:F3} ms");

TypeScript:

const startTime = performance.now();
// Your algorithm here
const duration = performance.now() - startTime;
console.log(`Algorithm took: ${duration.toFixed(3)} ms`);

Turn Timeout Considerations

Each bot has limited time per turn (default: 30ms):

• Simple bots: Usually complete in < 1ms
• Complex targeting: May take 5-15ms
• Slow algorithms: Risk timeout penalties

If your bot times out:

• Optimize algorithms (better data structures, fewer loops)
• Cache calculations when possible
• Reduce complexity of per-turn operations

For advanced performance optimization techniques, see Performance Optimization.

Test Harness Development

Automated Testing Scripts

Create scripts to run multiple battles and aggregate results:

Example test script (Bash):

#!/bin/bash
for i in {1..10}; do
  robocode-tankroyale-server --config=test-config.json >> results.txt
done

Recording Battle Statistics

Track key metrics across battles:

• Win rate percentage - Overall success rate
• Average score per round - Consistent performance measure
• Survival rate - Ability to avoid destruction
• Bullet hit percentage - Targeting accuracy

Regression Testing

After code changes:

1. Run test suite against saved bot versions
2. Compare win rates and scores
3. Investigate any significant performance drops
4. Keep baseline results for comparison

Common Testing Pitfalls

Insufficient sample size:

• Running too few battles leads to misleading results
• Use at least 35 rounds per opponent

Testing against weak opponents only:

• Your bot may overfit to weak strategies
• Include strong, diverse opponents

Optimizing for specific opponents:

• Avoid hardcoding behaviors for test bots
• Focus on generalizable strategies

Ignoring edge cases:

• Test in different arena sizes
• Test with various starting positions
• Test against multiple opponent types

Debugging Common Issues

Bot Doesn't Move

Possible causes:

• Forgetting to call movement methods (setForward(), setTurnRate())
• Setting contradictory commands
• Bot timing out due to slow code

Debugging:

• Print movement commands each turn
• Check for exceptions in console output
• Verify run() loop executes each turn

Bot Doesn't Fire

Possible causes:

• Gun heat > 0 (gun still cooling)
• No target scanned
• Invalid firepower (< 0.1 or > 3)

Debugging:

• Print gun heat each turn
• Verify enemy is being scanned
• Check firepower calculations

Erratic Behavior

Possible causes:

• Unhandled events overwriting planned actions
• State variables not updating correctly
• Calculation errors in targeting or movement

Debugging:

• Add extensive logging around decision points
• Visualize bot's "thought process" through debug output
• Test individual algorithms in isolation

Further Reading

• Debugging - Debug options and print debugging
• Custom Game Setup - Configure test battles
• Performance Optimization - Optimize bot execution speed
• APIs - Bot API documentation for all languages
• The Book of Robocode - Advanced strategies and testing methodologies