# Closed Loop Audio Test Suite

Simple Python-based testing system for PCB audio hardware validation.

## Features

- **Automated Testing**: Latency measurements with configurable iterations
- **Metadata Tracking**: Serial number, software version, timestamps, comments
- **YAML Output**: Human-readable structured results
- **Simple Workflow**: Run tests, view results, compare versions

## Quick Start

### 1. Install Dependencies

```bash
pip install -r requirements.txt
```

### 2. Run a Test

**Latency Test:**
```bash
python test_latency.py \
  --serial-number "SN001234" \
  --software-version "a3f2b1c" \
  --comment "Replaced capacitor C5"
```

**Artifact Detection Test:**
```bash
python test_artifact_detection.py \
  --serial-number "SN001234" \
  --software-version "a3f2b1c" \
  --comment "Baseline test"
```

### 3. View Results

```bash
# View specific test
python view_results.py test_results/20260226_123456_results.yaml

# List all tests
python view_results.py --list

# View latest test
python view_results.py test_results/*.yaml | tail -1
```

## Test Metrics

- **Latency**: Round-trip delay between input and output channels (ms)
  - Average, minimum, maximum, and standard deviation across measurements
  - Uses chirp signal for accurate cross-correlation measurement

## Output Format

Results are saved as YAML files in `test_results/`:

```yaml
metadata:
  test_id: 20260226_123456
  timestamp: '2026-02-26T12:34:56.789012'
  serial_number: SN001234
  software_version: a3f2b1c
  comment: Replaced capacitor C5
latency_test:
  avg: 2.345
  min: 2.201
  max: 2.489
  std: 0.087
```

## Configuration

Edit `config.yaml` to customize:
- Audio device settings
- Output options

```yaml
audio:
  sample_rate: 44100
  channels: 2
  device_name: "Scarlett"

output:
  results_dir: "test_results"
  save_plots: true
```

The system auto-detects Focusrite Scarlett audio interfaces.

## Hardware Setup

```
Laptop <-> Audio Interface (Scarlett) <-> DUT <-> Audio Interface (Scarlett) <-> Laptop
         Output Channels 1&2         Input Channels 1&2
```

## File Structure

```
closed_loop_audio_test_suite/
├── config.yaml              # Test configuration
├── test_latency.py          # Latency test runner
├── test_artifact_detection.py  # Artifact detection test
├── view_results.py          # Results viewer
├── src/
│   └── audio_tests.py       # Core test functions
└── test_results/            # YAML output files
    ├── YYYYMMDD_HHMMSS_latency/
    └── YYYYMMDD_HHMMSS_artifact_detection/
```

## Tips

- Each test run creates a timestamped YAML file
- Results are self-contained with full metadata
- Compare tests by opening multiple YAML files
- Archive old tests by moving YAML files to subdirectories