Advanced Networking Testing Strategies for MTG Commander

This document expands upon our core testing strategies with advanced test scenarios and methodologies specifically designed for the complex requirements of an online MTG Commander implementation.

Table of Contents

  1. Commander-Specific Testing
  2. Long-Running Game Tests
  3. Concurrency and Race Condition Testing
  4. Snapshot and Replay Testing
  5. Fault Injection Testing
  6. Load and Stress Testing
  7. Cross-Platform Testing
  8. Automated Test Generation
  9. Property-Based Testing
  10. Test Coverage Analysis

Commander-Specific Testing

Commander as a format has unique rules and complex card interactions that require specialized testing.

Multiplayer Politics Testing

Test how the networking handles multi-player political interactions:

#![allow(unused)]
fn main() {
#[test]
fn test_multiplayer_politics() {
    let mut app = setup_multiplayer_test_app(4); // 4 players
    
    // Simulate player 1 offering a deal to player 2
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::ProposeDeal {
            proposer: 1,
            target: 2,
            proposal: "I won't attack you this turn if you don't attack me next turn".to_string()
        });
    
    app.update_n_times(5); // Allow time for messages to propagate
    
    // Verify deal is visible to both players but hidden from others
    let client1 = get_client_view(&app, 1);
    let client2 = get_client_view(&app, 2);
    let client3 = get_client_view(&app, 3);
    let client4 = get_client_view(&app, 4);
    
    assert!(client1.can_see_proposal(proposal_id));
    assert!(client2.can_see_proposal(proposal_id));
    assert!(!client3.can_see_proposal(proposal_id));
    assert!(!client4.can_see_proposal(proposal_id));
    
    // Player 2 accepts deal
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::RespondToDeal {
            player: 2,
            proposal_id,
            response: ProposalResponse::Accept
        });
    
    app.update_n_times(5);
    
    // Verify deal acceptance is recorded and visible
    assert!(client1.proposals.contains_accepted(proposal_id));
    assert!(client2.proposals.contains_accepted(proposal_id));
}
}

Commander Damage Testing

Verify correct tracking and synchronization of commander damage:

#![allow(unused)]
fn main() {
#[test]
fn test_commander_damage_tracking() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Setup commanders for all players
    for player_id in 1..=4 {
        app.world.resource_mut::<TestController>()
            .setup_commander(player_id, commander_card_ids[player_id-1]);
    }
    
    // Player 1's commander deals damage to player 2
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::AttackWithCommander {
            attacker: 1,
            defender: 2,
            damage: 5
        });
    
    app.update_n_times(10);
    
    // Verify commander damage is tracked and synchronized
    for player_id in 1..=4 {
        let client = get_client_view(&app, player_id);
        
        // All players should see same commander damage value
        assert_eq!(
            client.commander_damage_received[2][1], 
            5,
            "Player {} sees incorrect commander damage", 
            player_id
        );
    }
    
    // Second attack with commander
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::AttackWithCommander {
            attacker: 1,
            defender: 2,
            damage: 6
        });
    
    app.update_n_times(10);
    
    // Check for player death from 21+ commander damage
    for player_id in 1..=4 {
        let client = get_client_view(&app, player_id);
        
        // Commander damage should be cumulative
        assert_eq!(client.commander_damage_received[2][1], 11);
        
        // Player 2 is still alive (under 21 damage)
        assert!(client.players[2].is_alive);
    }
    
    // Final attack for lethal commander damage
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::AttackWithCommander {
            attacker: 1,
            defender: 2,
            damage: 10
        });
    
    app.update_n_times(10);
    
    // Verify player death and synchronization
    for player_id in 1..=4 {
        let client = get_client_view(&app, player_id);
        
        // Player 2 should be dead from commander damage
        assert_eq!(client.commander_damage_received[2][1], 21);
        assert!(!client.players[2].is_alive);
        assert_eq!(
            client.players[2].death_reason, 
            DeathReason::CommanderDamage(1)
        );
    }
}
}

Long-Running Game Tests

MTG Commander games can be lengthy. We need to test stability and synchronization over extended play sessions.

#![allow(unused)]
fn main() {
#[test]
fn test_long_running_game() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Configure for extended test
    app.insert_resource(LongGameSimulation {
        turns_to_simulate: 20,
        actions_per_turn: 30,
        complexity_factor: 0.8, // Higher values = more complex actions
    });
    
    // Run the long game simulation
    app.add_systems(Update, long_game_simulation);
    
    // Run enough updates for the full simulation
    // (20 turns * 30 actions * 5 updates per action)
    app.update_n_times(20 * 30 * 5);
    
    // Assess results
    let metrics = app.world.resource::<GameMetrics>();
    
    // Check key reliability metrics
    assert!(metrics.desync_events == 0, "Game had state desynchronization events");
    assert!(metrics.error_count < 5, "Too many errors during extended play");
    assert!(metrics.network_bandwidth_average < MAX_BANDWIDTH_TARGET);
    
    // Verify final game state consistency
    verify_game_state_consistency(&app);
}
}

Concurrency and Race Condition Testing

Test for race conditions and concurrency issues that might occur when multiple network events arrive simultaneously:

#![allow(unused)]
fn main() {
#[test]
fn test_simultaneous_actions() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Create a scenario where multiple clients try to act at the exact same time
    let test_controller = app.world.resource_mut::<TestController>();
    
    // Configure test to deliver these actions "simultaneously" to the server
    test_controller.queue_simultaneous_actions(vec![
        (1, TestAction::CastSpell { card_id: 101, targets: vec![201] }),
        (2, TestAction::ActivateAbility { card_id: 202, ability_id: 1 }),
        (3, TestAction::PlayLand { card_id: 303 }),
    ]);
    
    // Process the simultaneous actions
    app.update();
    
    // Verify the server handled them in a deterministic order
    // and all clients ended up with the same state
    let server_state = extract_server_game_state(&app);
    
    for client_id in 1..=4 {
        let client_state = extract_client_game_state(&app, client_id);
        
        assert_eq!(
            server_state.action_history,
            client_state.action_history,
            "Client {} has different action order from server", 
            client_id
        );
    }
}
}

Snapshot and Replay Testing

Implement snapshot testing to capture and replay complex game states to ensure deterministic behavior:

#![allow(unused)]
fn main() {
#[test]
fn test_game_state_snapshot_restore() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Play several turns to reach a complex game state
    simulate_game_turns(&mut app, 5);
    
    // Take a snapshot of the current game state
    let snapshot = create_game_snapshot(&app);
    
    // Save snapshot to disk for future tests
    save_snapshot(&snapshot, "complex_board_state.snapshot");
    
    // Create a fresh app and restore the snapshot
    let mut restored_app = setup_multiplayer_test_app(4);
    restore_game_snapshot(&mut restored_app, &snapshot);
    
    // Verify restored state matches original
    let original_state = extract_game_state(&app);
    let restored_state = extract_game_state(&restored_app);
    
    assert_eq!(original_state, restored_state, "Restored state does not match original");
    
    // Execute identical actions on both instances
    let test_actions = generate_test_actions();
    
    for action in &test_actions {
        execute_action(&mut app, action);
        execute_action(&mut restored_app, action);
    }
    
    // Verify both instances end in identical states
    let final_original_state = extract_game_state(&app);
    let final_restored_state = extract_game_state(&restored_app);
    
    assert_eq!(
        final_original_state, 
        final_restored_state,
        "Divergent states after identical action sequences"
    );
}
}

Fault Injection Testing

Systematically introduce faults to verify the system's resilience:

#![allow(unused)]
fn main() {
#[test]
fn test_client_disconnect_reconnect() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Play several turns
    simulate_game_turns(&mut app, 3);
    
    // Force disconnect client 2
    app.world.resource_mut::<NetworkController>()
        .disconnect_client(2);
    
    // Continue game for a turn
    simulate_game_turns(&mut app, 1);
    
    // Snapshot game state before reconnection
    let state_before_reconnect = extract_game_state(&app);
    
    // Reconnect client 2
    app.world.resource_mut::<NetworkController>()
        .reconnect_client(2);
    
    // Allow time for state synchronization
    app.update_n_times(20);
    
    // Verify reconnected client has correct state
    let client2_state = extract_client_game_state(&app, 2);
    let server_state = extract_server_game_state(&app);
    
    assert_eq!(
        server_state.public_state,
        client2_state.public_state,
        "Reconnected client failed to synchronize state"
    );
    
    // Continue play and verify client 2 can take actions
    app.world.resource_mut::<TestController>()
        .execute_action(TestAction::PlayCard {
            player_id: 2,
            card_id: 123
        });
    
    app.update_n_times(5);
    
    // Verify action was processed
    let updated_state = extract_game_state(&app);
    assert!(updated_state.contains_played_card(2, 123));
}
}

Load and Stress Testing

Test how the system performs under high load:

#![allow(unused)]
fn main() {
#[test]
fn test_high_action_throughput() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Configure test with high action frequency
    app.insert_resource(ActionThroughputTest {
        actions_per_second: 50,
        test_duration_seconds: 30,
    });
    
    // Run stress test
    app.add_systems(Update, high_throughput_test);
    app.update_n_times(30 * 60); // 30 seconds at 60 fps
    
    // Collect performance metrics
    let metrics = app.world.resource::<PerformanceMetrics>();
    
    // Verify system maintained performance under load
    assert!(metrics.action_processing_success_rate > 0.95); // >95% successful
    assert!(metrics.average_frame_time < 16.67); // Maintain 60fps (16.67ms)
    assert!(metrics.network_bandwidth_max < MAX_BANDWIDTH_LIMIT);
    
    // Verify game state remained consistent despite high throughput
    verify_game_state_consistency(&app);
}
}

Cross-Platform Testing

Test networking across different platforms and configurations:

#![allow(unused)]
fn main() {
// This would be implemented in CI pipeline to test different combinations
fn test_cross_platform() {
    // Test matrix for different platforms/configurations
    let platforms = ["Windows", "MacOS", "Linux"];
    let network_conditions = [
        NetworkCondition::Ideal,
        NetworkCondition::Home,
        NetworkCondition::Mobile,
    ];
    
    for server_platform in &platforms {
        for client_platform in &platforms {
            for &network_condition in &network_conditions {
                // Create test configuration
                let test_config = CrossPlatformTest {
                    server_platform: server_platform.to_string(),
                    client_platform: client_platform.to_string(),
                    network_condition,
                };
                
                // This would trigger tests on CI infrastructure
                run_cross_platform_test(test_config);
            }
        }
    }
}
}

Automated Test Generation

Implement systems to automatically generate test scenarios:

#![allow(unused)]
fn main() {
#[test]
fn test_generated_scenarios() {
    let mut app = setup_multiplayer_test_app(4);
    
    // Generate random but valid test scenarios
    let scenario_generator = TestScenarioGenerator::new()
        .with_seed(12345) // For reproducibility
        .with_complexity(TestComplexity::High)
        .with_game_progress(GameProgress::MidGame)
        .with_focus(TestFocus::ComplexBoardStates);
    
    // Generate 10 different test scenarios
    for _ in 0..10 {
        let scenario = scenario_generator.generate();
        
        // Set up the test scenario
        setup_test_scenario(&mut app, &scenario);
        
        // Run the test actions
        for action in scenario.actions {
            app.world.resource_mut::<TestController>().execute_action(action);
            app.update_n_times(5);
        }
        
        // Verify game state is consistent and valid
        verify_game_state_consistency(&app);
        verify_game_rules_not_violated(&app);
        
        // Reset for next scenario
        app.world.resource_mut::<TestController>().reset_game();
    }
}
}

Property-Based Testing

Use property-based testing to verify game invariants hold under various conditions:

#![allow(unused)]
fn main() {
#[test]
fn test_game_invariants() {
    // Setup property testing
    proptest::proptest!(|(
        num_players in 2..=4usize,
        game_turns in 1..20usize,
        actions_per_turn in 1..30usize,
        network_latency_ms in 0..500u64,
        packet_loss_percent in 0.0..15.0f32,
    )| {
        // Create test app with the specified conditions
        let mut app = setup_multiplayer_test_app(num_players);
        
        // Configure network conditions
        app.insert_resource(NetworkSimulation {
            latency: Some(network_latency_ms),
            packet_loss: Some(packet_loss_percent / 100.0),
            jitter: Some(network_latency_ms / 5),
        });
        
        // Run simulation
        simulate_game_with_params(&mut app, game_turns, actions_per_turn);
        
        // Check invariants that should always hold true
        let game_state = extract_game_state(&app);
        
        // Invariant 1: All players have exactly 1 commander (if alive)
        for player_id in 1..=num_players {
            let player = &game_state.players[player_id-1];
            if player.is_alive {
                assert_eq!(player.commanders.len(), 1);
            }
        }
        
        // Invariant 2: Total cards in game remains constant
        assert_eq!(
            game_state.total_cards_in_game,
            STARTING_CARD_COUNT * num_players
        );
        
        // Invariant 3: No player has negative life
        for player in &game_state.players {
            assert!(player.life >= 0);
        }
        
        // Invariant 4: All clients have consistent public information
        verify_public_state_consistency(&app);
    });
}
}

Test Coverage Analysis

Implement analysis tools to track test coverage specifically for networking and multiplayer aspects:

#![allow(unused)]
fn main() {
#[test]
fn generate_test_coverage_report() {
    // Run all networking tests with coverage tracking
    let results = run_tests_with_coverage("networking::");
    
    // Analyze coverage results
    let coverage = NetworkingCoverageAnalysis::from_results(&results);
    
    // Generate coverage report
    let report = coverage.generate_report();
    
    // Output report to file
    std::fs::write("networking_coverage.html", report).unwrap();
    
    // Verify minimum coverage thresholds
    assert!(coverage.message_types_covered > 0.95); // >95% of message types tested
    assert!(coverage.error_handlers_covered > 0.9); // >90% of error handlers tested
    assert!(coverage.synchronization_paths_covered > 0.9); // >90% of sync paths tested
    
    // Print coverage summary
    println!("Network message coverage: {:.1}%", coverage.message_types_covered * 100.0);
    println!("Error handler coverage: {:.1}%", coverage.error_handlers_covered * 100.0);
    println!("Sync path coverage: {:.1}%", coverage.synchronization_paths_covered * 100.0);
}
}

By implementing these advanced testing strategies along with our core testing approaches, we can ensure our MTG Commander online implementation is robust, performant, and provides a faithful and enjoyable multiplayer experience across various network conditions and edge cases.