Without the actual code patch, it's challenging to provide a thorough code review. However, based on the information you provided, here are some general suggestions:

1. Check for any syntax errors after adding the new line.
2. Verify if the new unit test case for unit/type/string is correctly implemented, including proper assertions and expected outcomes.
3. Uncomment or remove the commented out lines related to other unit tests (unit/type/hash, unit/sort, unit/expire) if they are not necessary in this code patch.
4. Conduct thorough testing to ensure that the existing functionality of the code is not affected by the changes.

For a more detailed code review, please include the actual code patch or specific sections that require attention.