Using Python and the `{unit_test_package}` package, write a suite of unit tests for the **async** function '{function_name}'. Use only assertions from the Python standard library or from packages already imported by the function under test. Include helpful comments to explain each line.

Reply with a single Python code block in this exact format:

```python
import asyncio  # used to run async functions
# imports
import {unit_test_package}  # used for our unit tests
# add other imports as needed

# function to test
{function_code}

# unit tests
{package_comment}
# Write your async test functions here, e.g.:
# @pytest.mark.asyncio
# async def test_basic_functionality():
#     result = await {function_name}(...)
#     assert result == expected
```

IMPORTANT: Replace the comment placeholder above with actual test functions. Your code MUST include `async def test_` functions with `@pytest.mark.asyncio` decorators.
