[32/N] Add unit tests for BubbleSort, CocktailSort, SelectionSort, InsertionSort, MergeSort, Quicksort, Quickselect, and HeapSort algorithms

[karkir0003]

PR Stack

1. ⬅️ [1/N] Update CI to run frontend unit tests #91 (Add test infrastructure and Jest setup)
2. ⬅️ [2/N] Configure React Testing Library and Setup Tests #92 (Add unit tests for Header, Footer, and Blob components)
3. ⬅️ [3/N] Add unit tests for SideButton component #94 (Add unit tests for HomeScreen components (SideButton, SearchFilter))
4. ⬅️ [4/N] Add unit tests for SearchFilter component #95 (Add unit tests for AlgoScreen components (AlgoSection, Pseudocode, ModalSidebarSectionTab))
5. ⬅️ [6/N] Add unit tests for Blob mascot component #97 (Add unit tests for modals (BigOModal, InfoModals))
6. ⬅️ [5/N] Add unit tests for Header and Footer components #96 (Add unit tests for AlgorithmNotFound404 component)
7. ⬅️ [7/N] Add unit tests for AboutScreen screen #98 (Add unit tests for HomeScreen page)
8. ⬅️ [8/N] Add integration tests for HomeScreen screen #99 (Add unit tests for AboutScreen page)
9. ⬅️ [9/N] Add unit tests for AlgorithmNotFound404 component #100 (Add unit tests for AlgoScreen page)
10. ⬅️ [10/N] Add integration tests for AlgoScreen screen #101 (Add unit tests for App root component and routes)
11. ⬅️ [11/N] Add unit tests for ModalSidebarSectionTab component #102 (Add test coverage workflow for CI)
12. ⬅️ [12/N] Add unit tests for BigOModal component #103 (Add unit tests for CustomEvents animation utility)
13. ⬅️ [13/N] Add unit tests for Pseudocode component #104 (Add unit tests for UndoFunctions animation utility)
14. ⬅️ [14/N] Add unit and integration tests for AlgoSection component #105 (Add unit tests for AnimatedCircle animation primitive)
15. ⬅️ [15/N] Add unit and integration tests for root App component #106 (Add unit tests for AnimatedHighlightCircle)
16. ⬅️ [16/N] Add unit tests for animation events and undo functions #107 (Add unit tests for SingleAnimation)
17. ⬅️ [17/N] Add unit tests for AnimatedObject, AnimatedCircle, and AnimatedHighlightCircle #108 (Add unit tests for AnimatedObject base class)
18. ⬅️ [18/N] Add unit tests for AnimatedRectangle, AnimatedLabel, and AnimatedLine #109 (Add unit tests for AnimatedRectangle, AnimatedLabel, and AnimatedLine)
19. ⬅️ [19/N] Add unit tests for AnimatedLinkedListNode, AnimatedDoublyLinkedListNode, and AnimatedCircularlyLinkedListNode #110 (Add unit tests for AnimatedLinkedListNode, AnimatedDoublyLinkedListNode, and AnimatedCircularlyLinkedListNode)
20. ⬅️ [20/N] Add unit tests for AnimatedBTreeNode and AnimatedSkipListNode #111 (Add unit tests for AnimatedBTreeNode and AnimatedSkipListNode)
21. ⬅️ [21/N] Add unit tests for ObjectManager #112 (Add unit tests for ObjectManager)
22. ⬅️ [22/N] Add unit tests for AnimationMain #113 (Add unit tests for AnimationMain)
23. ⬅️ [23/N] Add unit tests for algo util helpers (PriorityQueue, SkipListHeads, GraphValues) #114 (Add unit tests for algo util helpers (PriorityQueue, SkipListHeads, GraphValues))
24. ⬅️ [24/N] Add unit tests for base Algorithm class and control bar helpers #115 (Add unit tests for base Algorithm class and control bar helpers)
25. ⬅️ [25/N] Add unit tests for ArrayList algorithm #116 (Add unit tests for ArrayList algorithm)
26. ⬅️ [26/N] Add unit tests for LinkedList, DoublyLinkedList, and CircularlyLinkedList algorithms #117 (Add unit tests for LinkedList, DoublyLinkedList, and CircularlyLinkedList algorithms)
27. ⬅️ [27/N] Add unit tests for Stack, Queue, and Deque algorithms (Array and LL variants) #118 (Add unit tests for Stack, Queue, and Deque algorithms (Array and LL variants))
28. ⬅️ [28/N] Add unit tests for BST, AVL, Heap, and SplayTree algorithms #119 (Add unit tests for BST, AVL, Heap, and SplayTree algorithms)
29. ⬅️ [29/N] Add unit tests for BTree, TreeMap, SkipList, and DisjointSet algorithms #120 (Add unit tests for BTree, TreeMap, SkipList, and DisjointSet algorithms)
30. ⬅️ [30/N] Add unit tests for Hash, OpenHash, ClosedHash, and NonLinearProbing algorithms #121 (Add unit tests for Hash, OpenHash, ClosedHash, and NonLinearProbing algorithms)
31. ⬅️ [31/N] Add unit tests for BruteForce, BoyerMoore, KMP, RabinKarp, and LCS pattern matching algorithms #122 (Add unit tests for BruteForce, BoyerMoore, KMP, RabinKarp, and LCS pattern matching algorithms)
32. 👉 #CURRENT — Add unit tests for BubbleSort, CocktailSort, SelectionSort, InsertionSort, MergeSort, Quicksort, Quickselect, and HeapSort algorithms (this PR)
33. ➡️ [33/N] Add unit tests for LSDRadix, RadixSort, BogoSort, DropSort, FredSort, MiracleSort, and SleepSort algorithms #124 (Add unit tests for LSDRadix, RadixSort, BogoSort, DropSort, FredSort, MiracleSort, and SleepSort algorithms)

---

Addresses #93

Context

Adds comprehensive unit test coverage for comparison-based sorting algorithms and order-statistic selection visualizers:

• BubbleSort.js: Standard bubble sort with adjacent comparisons, swap counter tracking, early termination pass check, and last-swap optimization toggle (toggleLastSwap).
• CocktailSort.js: Bidirectional cocktail shaker sort with alternating forward and backward bubbling passes, dual last-swap boundary tracking, and early termination.
• SelectionSort.js: In-place selection sort with minimum scanning, candidate element tracking, swap execution, and min/max variant selection callback (minCallback / maxCallback).
• InsertionSort.js: Insertion sort with sorted partition expansion, element shifting, key insertion animation, and comparison/swap metric updates.
• MergeSort.js: Recursive divide-and-conquer merge sort visualizer with sub-array block splitting, tree level hierarchy display, and merged array reconstruction.
• Quicksort.js: Quicksort with pivot selection modes (Random, First, Last), two-pointer partition scanning, pivot placement, and recursive boundary sorting.
• Quickselect.js: Quickselect order-statistic selection finding the k-th smallest element via partitioned pivot pruning, branch selection, and index target validation.
• HeapSort.js: In-place heap sort combining binary heap tree visualization and array representation, bottom-up max-heap construction (siftDown), and extract-max sorting passes.

Changes Made

• Introduced src/algo/__tests__/BubbleSort.test.js:
  • Control registration, sort button, preset values, random array generator, and clear actions.
  • Validation for array bounds (max 18 items), values > 999, and non-numeric inputs.
  • Comparison and swap counter increments, sorted element highlights, and early exit when sorted.
  • Last-swap optimization checkbox toggle and URL parameter parsing (lastSwap, data).
• Introduced src/algo/__tests__/CocktailSort.test.js:
  • Forward and backward bubbling passes, sorted boundary markers, and comparison/swap counters.
  • Validation checks, preset population, and random array generation.
  • Last-swap optimization toggle and URL parameter initialization.
• Introduced src/algo/__tests__/SelectionSort.test.js:
  • Control registration, validation (max 18 items, >999, non-numeric).
  • Min scanning pointer animations, swap execution, and counter tracking.
  • Min / Max variant selection callbacks and URL parameter parsing.
• Introduced src/algo/__tests__/InsertionSort.test.js:
  • Validation checks, preset loading, and random list generator.
  • Shifting and insertion animation sequences, comparison/swap tracking, and URL parameter parsing.
• Introduced src/algo/__tests__/MergeSort.test.js:
  • Validation (max 15 items, >999, non-numeric).
  • Sub-array splitting, recursive level placement, and merge reconstruction.
  • Preset examples, random generator, and URL parameter parsing.
• Introduced src/algo/__tests__/Quicksort.test.js:
  • Partitioning with left/right scanning pointers, pivot swapping, and recursive call tracking.
  • Pivot selection dropdown options and validation checks.
  • Preset values, random generator, and URL parameter parsing.
• Introduced src/algo/__tests__/Quickselect.test.js:
  • Input validation for array data and target k index boundaries.
  • run(list, k) execution with partition pruning directly to the target element.
  • Identification highlight of the k-th smallest element and URL parameter initialization (k, data).
• Introduced src/algo/__tests__/HeapSort.test.js:
  • Validation (max 15 items, >999, non-numeric).
  • Dual array and binary heap tree node setup (heapArrayData, heapArrayID, heapTreeObj).
  • Max-heapify phase (siftDown), extract-max passes, and sorted tree animation.
  • Preset values, random generation, and URL parameter parsing.

Test Plan

• Ran npm test -- --watchAll=false (all 8 new test suites pass, 86 unit tests passing; 68 suites, 765 tests passing repository-wide).
• Ran npm run lint and npm run prettier (0 errors, 0 warnings).