```json
{
  "files": [
    "client.py",
    "test_client.py"
  ],
  "edits": [
    {
      "file": "client.py",
      "description": "Initialize the httpx.Client with a default timeout of 10 seconds to handle hanging requests without altering the public method signatures.",
      "code": "import httpx\n\nclass APIClient:\n    def __init__(self, base_url: str):\n        # Added timeout=10.0 to the client initialization to handle request timeouts\n        self.client = httpx.Client(base_url=base_url, timeout=10.0)\n\n    def get_data(self, endpoint: str):\n        \"\"\"Fetches data from the specified endpoint.\"\"\"\n        response = self.client.get(endpoint)\n        response.raise_for_status()\n        return response.json()"
    }
  ],
  "tests": [
    {
      "file": "test_client.py",
      "description": "Verify that the client correctly raises a TimeoutException when a request exceeds the internal timeout limit.",
      "code": "import pytest\nimport httpx\nfrom unittest.mock import MagicMock\nfrom client import APIClient\n\ndef test_get_data_timeout_handling():\n    # Initialize client\n    client = APIClient(\"https://api.example.com\")\n    \n    # Mock the internal httpx.Client.get method to raise a TimeoutException\n    client.client.get = MagicMock(side_effect=httpx.TimeoutException(\"Request timed out\"))\n    \n    # Assert that the exception is propagated correctly\n    with pytest.raises(httpx.TimeoutException):\n        client.get_data(\"/slow-endpoint\")"
    }
  ],
  "risks": [
    "Hardcoded timeout (10.0s) may be insufficient for large payloads or slow legacy endpoints.",
    "Lack of per-request timeout flexibility: Since the public signature cannot be changed, callers cannot override the timeout for specific high-latency calls.",
    "Global timeout affects all requests made by the client instance, which might lead to premature failures on non-critical but slow operations."
  ]
}
```