Unit Test Generation Prompt

Write unit tests for the function below.
Language/framework: {{language/framework}}
Function:
```
{{function code}}
```

Requirements:
1. List inputs/outputs and five edge cases first.
2. Cover happy path, empty, extremes, invalid input, and exceptions.
3. One assertion per behavior; clear names.
4. Use table-driven/parameterized tests when supported.
5. Don't mock the function under test.
6. End with the run command.