# Test Failures — Iteration d009657d

## Summary
**All tests passed successfully!** No failures to report.

## Test Results
- **Total tests run**: 226
- **Passed**: 226
- **Failed**: 0
- **Ignored**: 0

## Coverage Analysis

### Acceptance Criteria Coverage

#### AC2.1 (partial): AST can represent function definition syntax
✅ **FULLY COVERED**
- Test: `test_function_def_construction_no_params`
- Test: `test_function_def_construction_with_params`
- Validates that AST can represent function definitions with name, params, and body

#### New Statement::FunctionDef variant with name (String), params (Vec<String>), body (Vec<Statement>)
✅ **FULLY COVERED**
- Test: `test_function_def_construction_no_params` - validates structure with empty params
- Test: `test_function_def_construction_with_params` - validates structure with multiple params
- Test: `test_function_def_nested_body` - validates complex body with multiple statement types
- Test: `test_function_with_many_params` - validates boundary condition with 50 parameters
- Test: `test_empty_function_body` - validates edge case with empty body
- Test: `test_function_body_with_all_statement_types` - validates body with all statement variants

#### New Statement::Return variant with value (Option<Expression>)
✅ **FULLY COVERED**
- Test: `test_return_with_value` - validates Return with Some(Expression)
- Test: `test_return_without_value` - validates Return with None
- Test: `test_return_equality` - validates PartialEq trait
- Test: `test_return_equality_with_none` - validates None equality behavior
- Test: `test_return_with_complex_nested_expression` - validates deeply nested expressions in return

#### New Expression::Call variant with name (String), args (Vec<Expression>)
✅ **FULLY COVERED**
- Test: `test_call_expression_no_args` - validates Call with empty args
- Test: `test_call_expression_with_args` - validates Call with multiple args
- Test: `test_call_with_complex_args` - validates Call with complex expression args
- Test: `test_call_with_many_args` - validates boundary condition with 50 arguments
- Test: `test_call_with_mixed_expression_types` - validates all expression types as args
- Test: `test_call_with_variable_args` - validates variable-only arguments

#### All existing AST tests continue to pass (regression check)
✅ **PASSED**
- All 9 pre-existing AST tests pass without modification
- No regressions detected in existing functionality

#### At least 10 new unit tests for function AST nodes (construction, equality, clone)
✅ **EXCEEDED** - 27 function-related tests total (14 by coder + 13 by QA)
- **Construction tests**: 10 tests covering all node types and edge cases
- **Equality tests**: 6 tests covering PartialEq for all function node variants
- **Clone tests**: 3 tests validating Clone trait implementation
- **Nesting tests**: 5 tests covering nested function calls and complex bodies
- **Edge case tests**: 3 tests for boundary conditions (empty names, many params/args, etc.)

## Edge Cases Added by QA

The following edge case tests were added to strengthen the test suite:

1. **test_empty_function_body** - Empty function bodies (valid AST, validation at compile time)
2. **test_function_with_many_params** - Boundary test with 50 parameters
3. **test_call_with_many_args** - Boundary test with 50 arguments
4. **test_empty_function_name** - Empty string as function name
5. **test_function_with_special_name** - Special characters in function names
6. **test_return_with_complex_nested_expression** - Deeply nested return expressions
7. **test_function_def_clone_independence** - Clone creates independent copies
8. **test_call_with_mixed_expression_types** - All expression types as call arguments
9. **test_function_body_with_all_statement_types** - All statement types in function body
10. **test_return_equality_with_none** - None return equality semantics
11. **test_call_with_variable_args** - Only variable arguments in call
12. **test_program_with_multiple_functions** - Multiple function definitions in program
13. **test_deeply_nested_function_calls_in_args** - Deep nesting of calls within calls

## Integration Notes

A minor compilation issue was identified and fixed:
- **Issue**: VM module had non-exhaustive match pattern for new bytecode instructions
- **Fix**: Added placeholder match arm for `DefineFunction`, `Call`, and `Return` instructions with `unimplemented!()`
- **Rationale**: Consistent with compiler approach; function execution will be implemented in future iteration
- **Impact**: No functional regression; all tests pass

## Conclusion

The coder's implementation **fully meets and exceeds** all acceptance criteria:
- ✅ All required AST variants are correctly implemented
- ✅ 27 comprehensive tests (exceeding the 10 required)
- ✅ Zero regressions (all 199+ existing tests pass)
- ✅ Robust edge case coverage added by QA
- ✅ All traits (Clone, PartialEq, Debug) correctly implemented
- ✅ Code compiles and all 226 tests pass

**Quality Assessment**: Excellent implementation with comprehensive test coverage.
