# Test Diagnostics Enhancement - Phase 1-2 Implementation Complete

## Summary

Successfully implemented enhanced diagnostic output for test failures in the `error_handling` feature. Tests now provide comprehensive context when they fail, making it much easier to debug issues.

## What Was Implemented

### 1. Diagnostic Utilities Module
**File:** `features/steps/diagnostic_utils.py`

- `format_execution_context()` - Formats complete execution context including commands, exit codes, stdout/stderr, files generated
- `format_comparison()` - Formats expected vs actual comparisons
- `assert_with_diagnostics()` - Enhanced assertion with automatic diagnostic attachment

### 2. Updated Step Definitions
**File:** `features/steps/error_handling/edge_cases.py`

Updated 4 critical assertion steps with enhanced diagnostics:

1. **`step_then_bom_generation_succeeds_with_exit_code`** (line 573)
   - Shows full execution context on exit code mismatch
   - Lists all files generated
   - Shows command output and errors

2. **`step_then_output_contains_warning`** (line 596)
   - Shows full stdout and stderr when warning not found
   - Case-insensitive matching with clear indication

3. **`step_then_bom_file_contains_unmatched_components`** (line 617)
   - Lists all searched filenames when BOM not found
   - Lists all CSV files actually found
   - Shows BOM preview when components missing

4. **`step_then_error_message_reports_and_exits_with_code`** (line 363)
   - Enhanced multi-modal validation
   - Shows failures for each method (CLI, API, Plugin) separately
   - Includes output snippets for context

### 3. Environment Setup
**File:** `features/environment.py`

- Added `steps` directory to Python path for module imports

## Example Output Comparison

### Before (Original)
```
Then the BOM generation succeeds with exit code 0
  ASSERT FAILED: Expected exit code 0, got 1
```

**Problem:** No information about what actually happened, what command was run, or what the error was.

### After (Enhanced)
```
Then the BOM generation succeeds with exit code 0
  ASSERTION FAILED: Exit code mismatch
    Expected: 0
    Actual:   1

  ================================================================================
  DIAGNOSTIC INFORMATION
  ================================================================================

  --- COMMAND EXECUTED ---
  CLI: jbom bom SimpleProject --inventory empty-inventory.csv

  Exit Code: 1

  --- STDOUT ---
  (empty)

  --- STDERR ---
  /opt/homebrew/opt/python@3.10/bin/python3.10: No module named jbom.cli.__main__;
  'jbom.cli' is a package and cannot be directly executed

  --- WORKING DIRECTORY ---
  /var/folders/.../scenario_Empty_inventory_file_with_header_only

  --- FILES GENERATED ---
    SimpleProject/SimpleProject.kicad_sch (433 bytes)
    empty-inventory.csv (53 bytes)

  ================================================================================
```

**Benefit:** Immediately see what went wrong - the CLI module import issue is now obvious.

## Testing Results

### Passing Scenarios
- Scenarios that pass show NO diagnostic output (clean, normal behavior)
- Example: "Output file permission denied" scenario passes cleanly

### Failing Scenarios
- Failures now show comprehensive diagnostic information
- Developer can immediately see:
  - What command was executed
  - What the actual exit code and output were
  - What files were generated
  - What the working directory was

## Files Modified

1. **Created:**
   - `features/steps/diagnostic_utils.py` (138 lines)
   - `docs/test_diagnostics_phase1-2_complete.md` (this file)

2. **Modified:**
   - `features/steps/error_handling/edge_cases.py` (4 step definitions)
   - `features/environment.py` (added Python path setup)

## Benefits Realized

1. **Faster Debugging** - Developers can see exactly what happened without re-running tests
2. **Better Error Context** - Full command output, files generated, and working directory shown
3. **Zero Impact on Passing Tests** - Diagnostics only appear on failures
4. **Multi-Modal Awareness** - Enhanced validation shows results for CLI, API, and Plugin separately

## Next Steps (Phase 3)

To apply these improvements to other features:

1. Update remaining error_handling steps (~10-15 more steps)
2. Apply to BOM feature steps (~15-20 steps)
3. Apply to POS feature steps (~8-10 steps)
4. Apply to inventory feature steps (~10-15 steps)
5. Apply to search feature steps (~5-8 steps)

## Usage Guidelines

### For Test Writers

When adding new assertion steps:

```python
from diagnostic_utils import assert_with_diagnostics, format_execution_context

@then("my new assertion")
def step_my_assertion(context):
    # For simple assertions
    assert_with_diagnostics(
        actual == expected,
        "Description of what failed",
        context,
        expected=expected,
        actual=actual,
    )

    # For custom error messages
    if not condition:
        diagnostic = (
            f"\nCustom failure message\n"
            f"  Detail 1: {value1}\n"
            f"  Detail 2: {value2}\n"
            + format_execution_context(context)
        )
        raise AssertionError(diagnostic)
```

### For Developers Debugging Tests

When a test fails:

1. **Look at STDERR first** - Often shows the root cause
2. **Check FILES GENERATED** - Verify test setup created expected files
3. **Review STDOUT** - May contain warnings or info messages
4. **Examine WORKING DIRECTORY** - Check if you're in the right place
5. **For multi-modal tests** - Compare results across CLI/API/Plugin to identify interface-specific issues

## Implementation Notes

- Diagnostics are formatted lazily (only when assertion fails)
- File listings are limited to 20 files to prevent overwhelming output
- Long output strings are truncated to 200 chars with "..." indicator
- Working directory and file paths use absolute paths for clarity

## Conclusion

Phase 1-2 implementation is **complete and tested**. The diagnostic utilities are working as designed, providing significant value when debugging test failures. Ready for user validation and feedback before proceeding to Phase 3.
