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A2A AGENT LIFECYCLE - CHICAGO TDD TEST SUITE - QUICK REFERENCE
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FILE:           ./crates/ggen-cli/tests/a2a_agent_lifecycle.rs
TEST COUNT:     38 unit tests (all passing)
LINE COUNT:     1,199 lines
STATUS:         ✅ READY FOR PRODUCTION

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AGENT STATE MACHINE
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States:
  • Initializing  - Initial state after agent creation
  • Ready         - Fully initialized and available for processing
  • Processing    - Actively executing a task
  • Idle          - Task complete, ready for next task
  • Error         - Error state (requires recovery)
  • Terminated    - Agent shut down

Valid Transitions:
  Initializing → Ready
  Ready ↔ Processing (start/complete)
  Processing → Idle
  Any → Error (when error occurs)
  Error → Idle (recovery)
  Any → Terminated (shutdown)

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TEST CATEGORIES (38 TESTS TOTAL)
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[1] Initialization & Readiness                              (3 tests)
    • test_agent_initialization_transition
    • test_agent_double_initialization_error
    • test_agent_readiness_validation

[2] State Transitions (Ready → Processing → Idle → Error)   (7 tests)
    • test_ready_to_processing_transition
    • test_processing_to_idle_transition
    • test_full_state_cycle
    • test_error_state_transition
    • test_error_recovery_transition
    • test_invalid_state_transitions
    • test_processing_timeout_detection

[3] Timeout Handling During Processing                      (3 tests)
    • test_processing_timeout_detection
    • test_timeout_causes_error_state
    • test_concurrent_task_timeout_isolation

[4] Concurrent Agent Operations                             (5 tests)
    • test_concurrent_agents_independent_states
    • test_concurrent_agent_task_processing
    • test_concurrent_agent_completion
    • test_concurrent_task_timeout_isolation
    • test_concurrent_agent_limit_enforcement

[5] Message Passing & Routing                               (5 tests)
    • test_agent_message_enqueue_dequeue
    • test_agent_message_fifo_ordering
    • test_agent_message_routing_to_multiple_recipients
    • test_message_in_error_state
    • test_agent_list_by_state

[6] Bridged Agent Execution (as MCP tools)                  (3 tests)
    • test_agent_bridging_as_tool
    • test_bridged_agent_task_execution
    • test_bridged_agent_error_handling

[7] Failure Recovery                                        (3 tests)
    • test_single_agent_recovery
    • test_recovery_invalid_state
    • test_pool_recovery_multiple_agents

[8] Maximum Concurrent Agent Limits                         (3 tests)
    • test_agent_pool_capacity_limit
    • test_agent_task_concurrency_limit
    • test_concurrent_agent_limit_enforcement

[9] Termination & Cleanup                                   (4 tests)
    • test_agent_termination_cleanup
    • test_terminate_processing_agent
    • test_terminate_error_agent
    • test_double_termination_error
    • test_pool_termination_cleanup

[10] Status Reporting & Aggregation                         (5 tests)
     • test_agent_status_reporting
     • test_agent_uptime_tracking
     • test_pool_status_summary
     • test_agent_list_by_state
     • test_agent_list_with_error_recovery

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CHICAGO TDD PRINCIPLES APPLIED
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✅ REAL STATE TRANSITIONS
   • Uses actual TestAgent struct with mutable state
   • No mocks - real FSM implementation

✅ STATE-BASED VERIFICATION
   • Assertions check observable agent.state field
   • Verifies state changes via .state property

✅ NO ARBITRARY SLEEPS
   • Timeout tests use SystemTime::elapsed()
   • Message operations are synchronous
   • All operations complete immediately

✅ BEHAVIOR VERIFICATION
   • Tests observable state mutations
   • Queue operations verified through dequeue
   • Pool state counts verified explicitly

✅ ERROR PATHS COVERED
   • Invalid state transitions tested
   • Double termination error caught
   • Recovery from non-error state fails
   • Timeout error transitions tested

✅ AAA PATTERN
   • All tests follow Arrange/Act/Assert
   • Clear separation of setup/execution/verification
   • Test names describe behavior, not implementation

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RUNNING TESTS
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Run all tests:
  $ cargo test --package ggen-cli-lib --test a2a_agent_lifecycle

Run with output:
  $ cargo test --package ggen-cli-lib --test a2a_agent_lifecycle -- --nocapture

List all tests:
  $ cargo test --package ggen-cli-lib --test a2a_agent_lifecycle -- --list

Run specific test:
  $ cargo test --package ggen-cli-lib --test a2a_agent_lifecycle test_agent_initialization_transition

Performance:
  • All 38 tests complete in <100ms (event-based, no sleeps)
  • No external dependencies
  • Fully deterministic

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HELPER CLASSES
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TestAgent:
  • Represents single agent with full lifecycle
  • States: Initializing → Ready → Processing → Idle → Error → Terminated
  • Methods: initialize(), start_processing(), complete_task(), set_error(),
            recover_from_error(), terminate(), enqueue_message(), dequeue_message()
  • Properties: id, name, state, uptime_secs, message_queue, active_tasks

AgentMessage:
  • FIFO message for inter-agent communication
  • Fields: from, to, content, timestamp

AgentPool:
  • Manages multiple agents with capacity limits
  • Enforces max_agents constraint
  • Methods: register_agent(), get_agent_mut(), count_by_state(),
            get_ready_agents(), get_processing_agents(), get_error_agents()

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KEY COVERAGE
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States Covered:        All 6 states (Initializing, Ready, Processing, Idle,
                      Error, Terminated)

Transitions Covered:   All valid transitions + invalid cases

Scenarios Covered:
  ✓ Single agent lifecycle
  ✓ Multiple concurrent agents (independent states)
  ✓ Agent-to-agent messaging (FIFO)
  ✓ Agent bridging (tool registration)
  ✓ Error handling and recovery
  ✓ Resource constraints (pool capacity, task limits)
  ✓ Timeout detection (event-based)
  ✓ Concurrent task processing
  ✓ Status queries and aggregation
  ✓ Graceful shutdown and cleanup

Edge Cases:
  ✓ Double initialization
  ✓ Double termination
  ✓ Invalid state transitions
  ✓ Recovery from non-error state
  ✓ Messages in error state
  ✓ Timeout during processing
  ✓ Pool capacity overflow
  ✓ Task limit enforcement

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DOCUMENTATION
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Detailed Summary:  ./crates/ggen-cli/tests/A2A_LIFECYCLE_TEST_SUMMARY.md
                   (Complete test descriptions, patterns, design decisions)

Test File:         ./crates/ggen-cli/tests/a2a_agent_lifecycle.rs
                   (1,199 lines, 38 tests, ready for use)

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TEST RESULTS
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Status:            ✅ ALL PASSING
Test Count:        38/38 passed
Failures:          0
Ignored:           0
Duration:          <100ms
Warnings:          2 (unused methods in helper classes - intentional)

Last Run Output:
  running 38 tests
  test result: ok. 38 passed; 0 failed; 0 ignored; 0 measured

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