Anjali Dewangan — R51-T041: Lock down the contract of reverseBits (fastFourierTransform.js) [src/algorithms/math/fourier-transform] #41

Student: Anjali Dewangan

Task: R51-T041 · 1 of 10
Repository: https://github.com/S-AI-Projects/javascript-algorithms
Assigned working branch: student/e26b07f0661

Goal

Work on src/algorithms/math/fourier-transform/fastFourierTransform.js. Create focused regression tests for reverseBits using the stated fixture. Test returned values and any observable mutation separately. Fixture: Use an empty supported value, a singleton and a three-element sequence [A,B,C], whose reverse is [C,B,A]. For strings, distinguish code points from bytes as documented.

Steps

1. Read src/algorithms/math/fourier-transform/fastFourierTransform.js, especially reverseBits near line 11. Record its public inputs, result, mutation behavior and any external dependencies before changing it.
2. Write independent expected results for the fixture before running the source. Run the baseline and explain any mismatch without assuming the implementation is correct.
3. Add a regression per distinct behavior; assert contents rather than just successful execution.
4. Implement work/R51-T041/check.py as a focused runner that executes the new checks and propagates failures. Native check to incorporate: run the repository test script in non-watch mode after installing from its lockfile; for browser-only code use a browser test instead of plain Node. Record the actual command and nonzero test count.
5. Create the checks specified below and run python3 work/R51-T041/check.py. Save inputs, expected versus actual results and tool versions in work/R51-T041/; a check must exit non-zero when an assertion fails.
6. Commit the repository change on branch R51-T041; prepare a PR to the organisation fork explaining the result and linking the checks. Keep each task independently reviewable. Remove work/R51-T041/ from a later upstream branch.

Done when

☐ The checked behavior is tied to reverseBits in src/algorithms/math/fourier-transform/fastFourierTransform.js; every assertion has an explicit expected value.
☐ Use an empty supported value, a singleton and a three-element sequence [A,B,C], whose reverse is [C,B,A]. For strings, distinguish code points from bytes as documented.
☐ Existing supported behavior and the public interface are preserved unless a failing regression demonstrates and documents a defect.
☐ The tests cover ordinary input, a smallest supported input and a repeated-value or equivalent domain boundary; each reports expected and actual results.

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.