Test Failure Analysis - Prompt 3b Implementation

Date: July 13, 2025
Scope: DSPex Adapter Infrastructure Test Failures
Status: Root Cause Analysis & Implementation Planning

Executive Summary

During the implementation of Prompt 3b adapter infrastructure components, we encountered 41 test failures out of 235 tests (82.6% pass rate). This document provides a comprehensive analysis of failure patterns, root causes, and implementation strategies to achieve 100% test compliance.

Test Failure Categorization

Category 1: Mock Adapter Process Management (32 failures - 78% of failures)

Pattern: GenServer.call(DSPex.Adapters.Mock, :reset, 5000) - no process: the process is not alive

Affected Tests:

• All Factory test suite setup failures
• Multiple behavior compliance test setup failures
• Process lifecycle management issues

Category 2: Signature Module Type Mismatch (8 failures - 20% of failures)

Pattern: BadMapError: expected a map, got: DSPex.Adapters.BehaviorComplianceTest.TestSignature

Affected Tests:

• Complex signature handling in behavior compliance tests
• Mock adapter expecting signature maps instead of signature modules

Category 3: Missing Function Dependencies (1 failure - 2% of failures)

Pattern: Function calls to non-existent or incorrectly implemented functions

Affected Areas:

• Registry adapter selection functions
• Factory-Registry integration points

Deep Root Cause Analysis

Category 1: Mock Adapter Process Management

Root Cause Theory #1: Process Registration Race Conditions

Hypothesis: Multiple test processes are attempting to start/register the same named GenServer simultaneously, causing registration conflicts and process crashes.

Supporting Evidence:

• Error occurs in setup phase across multiple test files
• Pattern: “no process: the process is not alive”
• Multiple Mock adapter started log entries appearing simultaneously

Test Strategy:

# Test 1.1: Process Registration Sequence
def test_process_registration_sequence do
  # Start multiple Mock processes with slight delays
  # Verify only one succeeds in registration
  # Check for race condition patterns
end

# Test 1.2: Process Lifecycle Isolation
def test_process_lifecycle_isolation do
  # Ensure each test gets clean Mock state
  # Verify process termination between tests
  # Check for zombie processes
end

Alternative Theory #1A: Test Setup Timing Issues If Theory #1 fails, consider that ExUnit’s async execution may be causing Mock processes to interfere with each other.

Mitigation Strategy for #1A:

• Change tests to async: false for Mock-dependent tests
• Implement process isolation per test
• Use unique process names per test

Root Cause Theory #2: Mock State Persistence Issues

Hypothesis: The Mock adapter is maintaining state across test boundaries, causing subsequent tests to fail when expecting clean state.

Supporting Evidence:

• reset() calls failing because process is already dead
• State corruption between test runs

Test Strategy:

# Test 2.1: State Isolation Verification
def test_state_isolation do
  # Run sequence of tests that modify Mock state
  # Verify each test starts with clean state
  # Check for state leakage between tests
end

# Test 2.2: Process Cleanup Verification
def test_process_cleanup do
  # Verify Mock process terminates after each test
  # Check for proper cleanup in test teardown
end

Category 2: Signature Module Type Mismatch

Root Cause Theory #3: Mock Adapter Signature Handling

Hypothesis: The Mock adapter’s generate_mock_response/3 function expects signature data as a map but receives a module reference instead.

Supporting Evidence:

• Map.get(DSPex.Adapters.BehaviorComplianceTest.TestSignature, "outputs", nil)
• Error occurs in mock.ex:447 during response generation

Test Strategy:

# Test 3.1: Signature Format Verification
def test_signature_format_verification do
  # Verify signature modules provide __signature__() function
  # Check format of returned signature data
  # Validate Mock adapter expects correct format
end

# Test 3.2: Signature Conversion Pipeline
def test_signature_conversion_pipeline do
  # Test signature module -> map conversion
  # Verify Factory properly converts signatures before Mock
  # Check TypeConverter signature format handling
end

Alternative Theory #3A: Factory-Mock Integration Gap If Theory #3 fails, the issue may be in the Factory’s signature processing before passing to Mock.

Mitigation Strategy for #3A:

• Implement signature module resolution in Factory
• Add signature format validation layer
• Create adapter-specific signature conversion

Root Cause Theory #4: Test Signature Module Implementation

Hypothesis: The test signature modules using @signature_ast attribute may not be properly implementing the signature behavior expected by adapters.

Supporting Evidence:

• Manual AST definition instead of DSL
• Potential mismatch between test signatures and production signatures

Test Strategy:

# Test 4.1: Test Signature Behavior Verification
def test_signature_behavior_verification do
  # Verify test signature modules implement required functions
  # Check __signature__() function returns proper format
  # Validate against known working signatures
end

Category 3: Missing Function Dependencies

Root Cause Theory #5: Registry-Factory Integration Gaps

Hypothesis: Factory is calling Registry functions that don’t exist or have changed signatures.

Test Strategy:

# Test 5.1: Registry Function Availability
def test_registry_function_availability do
  # Verify all Registry functions Factory expects exist
  # Check function signatures match expectations
  # Validate Registry adapter resolution logic
end

Implementation Plan

Phase 1: Process Management Stabilization (Priority: Critical)

Step 1.1: Mock Adapter Process Isolation

Objective: Ensure each test gets a clean Mock adapter process

Implementation:

# In test setup
defp setup_isolated_mock do
  # Kill any existing Mock process
  if pid = Process.whereis(DSPex.Adapters.Mock) do
    Process.exit(pid, :kill)
    Process.sleep(10) # Allow cleanup
  end
  
  # Start fresh Mock with unique name if needed
  {:ok, _} = DSPex.Adapters.Mock.start_link(name: :"mock_#{:erlang.unique_integer()}")
end

Step 1.2: Test Synchronization

Objective: Prevent race conditions in test execution

Implementation:

• Convert Mock-dependent tests to async: false
• Implement test-level process cleanup
• Add process status verification in setup

Validation Criteria:

• All Mock process management tests pass
• No “process not alive” errors in test runs
• Clean Mock state between tests verified

Phase 2: Signature Integration Resolution (Priority: High)

Step 2.1: Mock Adapter Signature Handling Fix

Objective: Ensure Mock adapter properly handles signature modules

Implementation:

# In mock.ex - generate_mock_response/3
defp extract_signature_data(signature) when is_atom(signature) do
  # Handle signature module
  signature.__signature__()
end

defp extract_signature_data(signature) when is_map(signature) do
  # Handle signature map
  signature
end

Step 2.2: Factory Signature Processing

Objective: Ensure Factory properly converts signatures for adapters

Implementation:

# In factory.ex
defp prepare_signature_for_adapter(signature_module, adapter) do
  case adapter do
    DSPex.Adapters.Mock ->
      # Mock expects signature data, not module
      signature_module.__signature__()
    _ ->
      # Other adapters handle modules directly
      signature_module
  end
end

Validation Criteria:

• Mock adapter accepts both signature modules and maps
• Factory properly converts signatures per adapter needs
• All signature-related tests pass

Phase 3: Test Infrastructure Hardening (Priority: Medium)

Step 3.1: Test Signature Standardization

Objective: Ensure all test signatures properly implement expected behavior

Implementation:

• Validate all test signature modules have __signature__() function
• Standardize signature format across test modules
• Add signature validation helpers

Step 3.2: Registry-Factory Integration Verification

Objective: Ensure all expected functions exist and work correctly

Implementation:

• Audit all Factory calls to Registry
• Implement missing Registry functions if needed
• Add integration test coverage

Validation Criteria:

• All test signatures implement standard interface
• Registry-Factory integration fully functional
• 100% test pass rate achieved

Testing Strategy Implementation

Hypothesis Testing Protocol

For Each Root Cause Theory:

1. Isolate the Component: Create minimal reproduction case
2. Test the Theory: Implement specific test to validate/invalidate
3. Measure Impact: Run focused test suite to measure improvement
4. Document Results: Record findings and update theories
5. Iterate: If theory invalid, test alternative theories

Iteration Framework:

Theory → Test → Measure → Analyze → 
  ↓
Valid? → Implement Fix → Validate → Next Theory
  ↓
Invalid? → Alternative Theory → Test → ...

Success Metrics

Phase 1 Success:

• 0 process management failures
• All Mock adapter tests pass in isolation
• Clean test setup/teardown verified

Phase 2 Success:

• 0 signature type mismatch errors
• Mock adapter handles all signature formats
• Factory-adapter integration working

Phase 3 Success:

• 100% test pass rate
• All infrastructure components working together
• Full Prompt 3b compliance achieved

Risk Mitigation

High-Risk Scenarios:

Risk 1: Mock Adapter Architecture Incompatibility

Mitigation:

• Implement adapter interface standardization
• Create mock-specific signature handling layer
• Add comprehensive adapter compatibility tests

Risk 2: Test Framework Limitations

Mitigation:

• Implement custom test isolation mechanisms
• Add process management utilities
• Create test-specific adapter instances

Risk 3: Signature System Design Issues

Mitigation:

• Standardize signature interface across all components
• Implement signature validation pipeline
• Add backward compatibility layer

Monitoring and Validation

Continuous Validation Strategy:

1. Automated Test Runs: Every change triggers full test suite
2. Failure Pattern Detection: Monitor for recurring failure patterns
3. Performance Metrics: Track test execution time and stability
4. Integration Verification: Regular end-to-end testing

Success Indicators:

• 100% test pass rate maintained
• No process management issues
• All signature formats handled correctly
• Factory-Registry integration stable
• Full Prompt 3b infrastructure operational

Implementation Timeline

Immediate (Next 2 hours):

• Phase 1: Process management fixes
• Initial testing and validation

Short-term (Today):

• Phase 2: Signature integration resolution
• Comprehensive testing of fixes

Medium-term (This week):

• Phase 3: Infrastructure hardening
• Full validation and documentation
• Performance optimization

This analysis provides the foundation for systematically resolving all test failures and achieving 100% compliance with Prompt 3b specifications.