# Async Mock Pattern for httpx.AsyncClient

## Problem
Tests were failing because async context managers weren't properly mocked.

## Solution - Helper Function
A `setup_mock_http_client()` helper has been created to properly mock httpx.AsyncClient.

## Usage Pattern

### For Successful Responses
```python
@pytest.mark.asyncio
@patch('app.services.pd_api_client.httpx.AsyncClient')
async def test_get_positions(self, mock_client_class, api_client, mock_data):
    """Test fetching positions"""
    # Setup mock using helper
    mock_client = setup_mock_http_client(
        mock_client_class,
        response_data=[mock_data]
    )

    # Execute
    ratings = await api_client.get_position_ratings(8807)

    # Verify
    assert len(ratings) == 1
    mock_client.get.assert_called_once()
```

### For Exceptions
```python
@pytest.mark.asyncio
@patch('app.services.pd_api_client.httpx.AsyncClient')
async def test_timeout_error(self, mock_client_class, api_client):
    """Test handling timeout"""
    # Setup mock to raise exception
    mock_client = setup_mock_http_client(
        mock_client_class,
        exception=httpx.TimeoutException("Request timeout")
    )

    # Execute and verify exception
    with pytest.raises(httpx.TimeoutException):
        await api_client.get_position_ratings(8807)
```

## Remaining Work

Update these test methods to use `setup_mock_http_client()` helper:

1. `test_get_multiple_positions` - Replace mock setup with helper
2. `test_get_positions_with_filter` - Replace mock setup with helper
3. `test_get_positions_wrapped_in_positions_key` - Replace mock setup with helper
4. `test_http_404_error` - Use helper with exception parameter
5. `test_http_500_error` - Use helper with exception parameter
6. `test_timeout_error` - Use helper with exception parameter
7. `test_connection_error` - Use helper with exception parameter
8. `test_malformed_json_response` - Use helper with exception parameter
9. `test_all_fields_parsed` - Replace mock setup with helper
10. `test_optional_fields_none` - Replace mock setup with helper

## Example Replacement

### Before (Broken)
```python
@patch('httpx.AsyncClient')
async def test_example(self, mock_client_class, api_client):
    mock_response = AsyncMock()
    mock_response.json.return_value = [data]
    mock_client = AsyncMock()
    mock_client.get.return_value = mock_response
    mock_client.__aenter__.return_value = mock_client
    mock_client_class.return_value = mock_client
    # ...
```

### After (Fixed)
```python
@patch('app.services.pd_api_client.httpx.AsyncClient')
async def test_example(self, mock_client_class, api_client):
    mock_client = setup_mock_http_client(mock_client_class, response_data=[data])
    # ...
```

## Key Points

1. **Patch path**: Use `'app.services.pd_api_client.httpx.AsyncClient'` not `'httpx.AsyncClient'`
2. **Context manager**: Helper properly sets up `__aenter__` and `__aexit__` as AsyncMocks
3. **Response**: Helper returns mock_client for additional assertions
4. **Exceptions**: Use `exception` parameter instead of `response_data`

## Estimated Time to Complete
~20-30 minutes to update all 10 remaining tests using find/replace pattern.