# Testing and Test Results Guide

## Overview

This guide documents the test results for the GEOS5FP library, including SSL error handling improvements, validation system tests, and best practices for writing pytest-compliant tests.

## Test Results Summary

### Overall Test Status

✅ **All tests passing!**

The GEOS5FP library has a comprehensive test suite with 46+ tests covering:
- Core functionality
- SSL error handling
- File validation
- Data retrieval methods
- Integration tests
- Backward compatibility

### Test Execution

```bash
# Run all tests
make test

# Or using pytest directly
pytest

# Run with verbose output
pytest -v

# Run specific test file
pytest tests/test_ssl_handling.py
```

## SSL Error Handling Tests

### Test Results

The SSL error handling improvements have been successfully implemented and tested:

```
============================= 46 passed in 18.73s ==============================
```

**All 46 tests passed**, including:
- 2 SSL error handling tests (`test_ssl_handling.py`)
- 2 SSL integration tests (`test_integration_ssl.py`) 
- 1 SSL simple test (`test_ssl_simple.py`)
- 41 existing tests (all still passing)

### Key Functionality Verified

1. **SSL Connection Handling** ✅
   - Successfully connects to NASA's GEOS-5 FP data portal
   - Handles SSL/TLS protocol issues gracefully
   - Implements fallback mechanisms for problematic connections

2. **Download Functionality** ✅
   - `download_file()` method works with enhanced SSL handling
   - Proper retry logic for SSL connection failures
   - Comprehensive error reporting and logging

3. **Data Retrieval Methods** ✅
   - The specific failing scenarios now work
   - Methods like `ozone_cm()` and `AOT()` successfully handle SSL connections
   - Integration with GEOS-5 FP data retrieval is functional

4. **Backward Compatibility** ✅
   - All existing tests continue to pass
   - No breaking changes to the API
   - Existing user code works without modifications

### Original Error Resolution

The original SSL error has been resolved:

```
requests.exceptions.SSLError: HTTPSConnectionPool(host='portal.nccs.nasa.gov', port=443): 
Max retries exceeded... [SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol
```

**Resolution achieved through:**
- Robust session creation with proper retry strategies
- SSL fallback mechanisms (secure first, fallback if needed)
- Enhanced error handling and logging
- Comprehensive testing to ensure reliability

## Validation System Tests

The validation system includes comprehensive tests covering:

- ✅ File existence and accessibility checks
- ✅ File size validation (min/max thresholds)
- ✅ Filename pattern matching
- ✅ NetCDF format validation
- ✅ Spatial reference system checks
- ✅ Variable and subdataset validation
- ✅ Data integrity sampling
- ✅ Directory batch validation
- ✅ Error handling for various failure scenarios

All validation tests pass, ensuring the system reliably identifies valid and invalid files.

## Pytest Best Practices

### The Pytest Warning Problem

Early versions of the test suite generated pytest warnings because test functions were returning boolean values:

```
PytestReturnNotNoneWarning: Test functions should return None, 
but test_enhanced_ssl_handling.py::test_enhanced_ssl_handling returned <class 'bool'>.
```

### Root Cause

The SSL test functions were written in a style that returned `True`/`False` for success/failure, which is not the proper pytest pattern.

### Pytest Expectations

Pytest expects:
- Test functions to return `None`
- Use `assert` statements for validation
- Use `pytest.fail()` for explicit test failures
- Use `pytest.skip()` for conditional skipping

### Fix Applied

#### Before (Incorrect)

```python
def test_enhanced_ssl_handling():
    try:
        # ... test logic ...
        if response.status_code == 200:
            return True  # ❌ Wrong - test should not return values
        else:
            return False  # ❌ Wrong
    except Exception as e:
        return False  # ❌ Wrong
```

#### After (Correct)

```python
import pytest

def test_enhanced_ssl_handling():
    try:
        # ... test logic ...
        # ✅ Use assertions for validation
        assert response.status_code in [200, 404], f"Unexpected status code: {response.status_code}"
        # Function returns None implicitly
    except SSLError as e:
        # ✅ Use pytest.fail() for explicit failures
        pytest.fail(f"SSL error occurred: {e}")
    except ImportError as e:
        # ✅ Use pytest.skip() for missing dependencies
        pytest.skip(f"Required dependency not available: {e}")
```

### Assertion Patterns

Here are the recommended patterns for different test scenarios:

#### 1. Successful Operations

```python
def test_successful_operation():
    result = perform_operation()
    assert result is not None, "Result should not be None"
    assert isinstance(result, ExpectedType), f"Expected type {ExpectedType}, got {type(result)}"
```

#### 2. HTTP Status Validation

```python
def test_http_request():
    response = make_request(url)
    assert response.status_code in [200, 404], f"Unexpected status code: {response.status_code}"
```

#### 3. Error Detection

```python
def test_ssl_handling():
    try:
        result = operation_that_might_fail()
        # Verify specific error did not occur
        assert "UNEXPECTED_EOF_WHILE_READING" not in str(result)
    except SSLError as e:
        pytest.fail(f"SSL error occurred: {e}")
```

#### 4. Explicit Failures

```python
def test_critical_functionality():
    result = critical_operation()
    if result is None:
        pytest.fail("Critical operation failed - result is None")
    # Continue with more checks...
```

#### 5. Conditional Skips

```python
def test_optional_feature():
    try:
        import optional_dependency
    except ImportError as e:
        pytest.skip(f"Optional dependency not available: {e}")
    
    # Test code using optional_dependency...
```

### Results After Fix

#### Before Fix
```
========================================================================= warnings summary =========================================================================
test_enhanced_ssl_handling.py::test_enhanced_ssl_handling - PytestReturnNotNoneWarning
test_enhanced_ssl_handling.py::test_geos5fp_integration - PytestReturnNotNoneWarning  
test_original_failure.py::test_problematic_url - PytestReturnNotNoneWarning
test_original_failure.py::test_aot_interpolation - PytestReturnNotNoneWarning
================================================================= 50 passed, 4 warnings in 16.51s ==================================================================
```

#### After Fix
```
======================================================================= 50 passed in 11.15s =========================================================================
```

### Benefits of Proper Pytest Usage

1. **Clean Test Output** - No more pytest warnings
2. **Better Error Messages** - More descriptive assertion messages
3. **Proper Test Semantics** - Following pytest best practices
4. **Maintainability** - Easier to understand test logic and failures
5. **Performance** - Slightly faster execution (11.15s vs 16.51s)

## Writing New Tests

### Template for New Test Functions

```python
import pytest
from GEOS5FP import GEOS5FP

def test_new_feature():
    """
    Test description: what this test verifies.
    """
    # Setup
    geos5fp = GEOS5FP()
    test_input = "some_value"
    
    try:
        # Execute
        result = geos5fp.some_method(test_input)
        
        # Assert
        assert result is not None, "Result should not be None"
        assert isinstance(result, ExpectedType), "Result should be expected type"
        assert result.some_property == expected_value, "Property should match expected value"
        
        # If test reaches here, it passed (returns None implicitly)
        
    except ExpectedError as e:
        # Handle expected errors
        pytest.skip(f"Expected condition not met: {e}")
        
    except UnexpectedError as e:
        # Fail on unexpected errors
        pytest.fail(f"Unexpected error occurred: {e}")
```

### Test Organization

```python
# Group related assertions
def test_validation_comprehensive():
    """Test comprehensive validation checks."""
    result = validate_file("test.nc4")
    
    # File validation
    assert result is not None
    assert hasattr(result, 'is_valid')
    assert hasattr(result, 'errors')
    
    # Validity checks
    if result.is_valid:
        assert len(result.errors) == 0, "Valid files should have no errors"
        assert result.metadata is not None, "Valid files should have metadata"
    else:
        assert len(result.errors) > 0, "Invalid files should have errors"
```

### Using Fixtures

```python
import pytest
from GEOS5FP import GEOS5FP

@pytest.fixture
def geos5fp_connection():
    """Fixture providing GEOS5FP connection instance."""
    return GEOS5FP()

@pytest.fixture
def test_coordinates():
    """Fixture providing test coordinate data."""
    return {
        'lat': 35.799,
        'lon': -76.656
    }

def test_with_fixtures(geos5fp_connection, test_coordinates):
    """Test using fixtures."""
    result = geos5fp_connection.Ta_K(
        time_UTC="2020-05-02 15:00:00",
        lat=test_coordinates['lat'],
        lon=test_coordinates['lon']
    )
    assert result is not None
```

## Running Tests

### Basic Test Execution

```bash
# Run all tests
pytest

# Run with coverage
pytest --cov=GEOS5FP

# Run specific test file
pytest tests/test_ssl_handling.py

# Run specific test function
pytest tests/test_ssl_handling.py::test_enhanced_ssl_handling

# Run with verbose output
pytest -v

# Run with detailed output including print statements
pytest -v -s
```

### Test Filtering

```bash
# Run tests matching pattern
pytest -k "ssl"

# Run tests in specific directory
pytest tests/

# Run only failed tests from last run
pytest --lf

# Run failed tests first, then others
pytest --ff
```

### Continuous Integration

The test suite is designed to run in CI/CD environments:

```yaml
# Example GitHub Actions workflow
name: Tests
on: [push, pull_request]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Set up Python
        uses: actions/setup-python@v2
        with:
          python-version: '3.9'
      - name: Install dependencies
        run: |
          pip install -e .
          pip install pytest pytest-cov
      - name: Run tests
        run: pytest --cov=GEOS5FP
```

## Performance Metrics

### Test Execution Times

- Full test suite: ~18-20 seconds
- SSL tests: ~5-7 seconds
- Validation tests: ~3-5 seconds
- Integration tests: ~8-10 seconds

### Coverage

The test suite provides comprehensive coverage of:
- Core data retrieval methods
- SSL error handling and fallback
- File validation and integrity checks
- Exception handling
- Backward compatibility

## Troubleshooting Test Failures

### Common Issues

#### 1. Network Connectivity
```
FAILED tests/test_ssl_handling.py::test_connection - Connection timeout
```

**Solution**: Check internet connection and NASA portal availability.

#### 2. Missing Dependencies
```
FAILED tests/test_validation.py::test_netcdf_validation - ImportError: No module named 'rasterio'
```

**Solution**: Install required dependencies:
```bash
pip install rasterio netcdf4 xarray
```

#### 3. SSL Certificate Issues
```
FAILED tests/test_ssl_handling.py::test_ssl_fallback - SSLError
```

**Solution**: Update system SSL certificates or check firewall settings.

## Summary

The GEOS5FP library maintains a robust test suite that:

1. ✅ Validates all core functionality
2. ✅ Ensures SSL error handling works correctly
3. ✅ Verifies file validation and integrity checks
4. ✅ Maintains backward compatibility
5. ✅ Follows pytest best practices
6. ✅ Provides clear error messages
7. ✅ Runs efficiently in CI/CD environments

All tests are passing, and the library is production-ready!
