Raj Manoj Patil — R23-T034: Property tests for strings/edit_distance.py #36

Student: Raj Manoj Patil

Task: R23-T034 · 4 of 10
Repository: https://github.com/S-AI-Projects/TheAlgorithms-Python
Assigned working branch: student/e26b07f0759

Goal

Use Hypothesis to test the code against a trusted reference or a mathematical property over thousands of random inputs. Metric properties: d(a,a)=0, d(a,b)=d(b,a), d(a,c) ≤ d(a,b)+d(b,c), and |len(a)-len(b)| ≤ d(a,b) ≤ max(len(a),len(b)).

Steps

1. Write test_edit_distance_properties.py in work/R23-T034/ using hypothesis strategies.
2. Implement the property/reference checks described in the goal.
3. Run it; if Hypothesis finds a failing input, reduce it to a minimal example and either fix the code (with a doctest) or document the limitation.
4. Explain each property in PROPERTIES.md.
5. Make the code change in the repository: strings/edit_distance.py: doctests for metric properties (symmetry, identical strings, empty strings) and validation for non-string input. Re-run the automated check and the repo's own tests afterwards.
6. Prepare the PR: on branch R23-T034, commit the code change plus your work/R23-T034/ evidence, put your findings in the PR description and open the PR against the org fork. For a later upstream PR, create a second branch containing only the code change (no work/ folder).

Done when

☐ Property tests: d(a,a)=0, d(a,b)=d(b,a), the triangle inequality, and |len(a)−len(b)| ≤ d(a,b) ≤ max(len(a),len(b)), each over ≥1,000 examples.
☐ strings/edit_distance.py gains doctests for empty strings and symmetry and a TypeError for non-strings.
☐ Existing 8 doctests pass (strings/edit_distance.py).

Submission checklist

• Complete this task and its checks.
• Add the required evidence and link your pull request here.
• Select this S-AI-Projects fork as the PR base repository.
• Request instructor review.

Keep this PR focused on this task. Do not submit assignment PRs to the upstream repository.