[30/N] Add unit tests for Hash, OpenHash, ClosedHash, and NonLinearProbing algorithms

[karkir0003]

🥞 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 Footer, Header, and Blob components)
3. ⬅️ [3/N] Add unit tests for SideButton component #94 (Add unit tests for AlgorithmNotFound404 component)
4. ⬅️ [4/N] Add unit tests for SearchFilter component #95 (Add unit tests for Pseudocode component)
5. ⬅️ [5/N] Add unit tests for Header and Footer components #96 (Add unit tests for AlgoSection component)
6. ⬅️ [6/N] Add unit tests for Blob mascot component #97 (Add unit tests for ModalSidebarSectionTab component)
7. ⬅️ [7/N] Add unit tests for AboutScreen screen #98 (Add unit tests for BigOModal component)
8. ⬅️ [8/N] Add integration tests for HomeScreen screen #99 (Add unit tests for InfoModals component)
9. ⬅️ [9/N] Add unit tests for AlgorithmNotFound404 component #100 (Add unit tests for SideButton component)
10. ⬅️ [10/N] Add integration tests for AlgoScreen screen #101 (Add unit tests for SearchFilter component)
11. ⬅️ [11/N] Add unit tests for ModalSidebarSectionTab component #102 (Add unit tests for HomeScreen)
12. ⬅️ [12/N] Add unit tests for BigOModal component #103 (Add unit tests for AboutScreen)
13. ⬅️ [13/N] Add unit tests for Pseudocode component #104 (Add unit tests for AlgoScreen)
14. ⬅️ [14/N] Add unit and integration tests for AlgoSection component #105 (Add unit tests for AlgoList registry)
15. ⬅️ [15/N] Add unit and integration tests for root App component #106 (Add unit and integration tests for root App component)
16. ⬅️ [16/N] Add unit tests for animation events and undo functions #107 (Add unit tests for animation events and undo functions)
17. ⬅️ [17/N] Add unit tests for AnimatedObject, AnimatedCircle, and AnimatedHighlightCircle #108 (Add unit tests for AnimatedObject, AnimatedCircle, and AnimatedHighlightCircle)
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. 👉 #CURRENT — Add unit tests for Hash, OpenHash, ClosedHash, and NonLinearProbing algorithms (this PR)
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)

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Addresses #93

Context

Adds comprehensive unit test coverage for the hash table algorithm visualizers:

• Hash.js: Base hash table controller, key/value input fields, initial capacity controls, integer and string hashing arithmetic (doHash), and URL serialization.
• OpenHash.js: Open addressing hash table supporting linear probing, quadratic probing, and double hashing collision strategies with tombstone markers and table resizing.
• ClosedHash.js: Separate chaining hash table using linked bucket chains, handling head insertion, duplicate updates, chain traversal, deletion, and capacity expansion.
• NonLinearProbing.js: Non-linear mathematical probing functions (sin, exponential, quadratic, logarithmic, multiplicative inverse), map filling, and collision management.

Changes Made

• Introduced src/algo/__tests__/Hash.test.js:
  • Control registration (key, value, insert, delete, find, load factor, initial capacity, restart).
  • Key types (integers, strings, true) switching and keyboard submission event wiring.
  • Integer modulo hashing and string character bitwise hashing animation routines.
  • Parameter parsing via setURLData (initialCapacity, loadFactor, hashType, key:val data pairs).
• Introduced src/algo/__tests__/OpenHash.test.js:
  • Open addressing table setup with empty flags and deleted tombstones.
  • Probing modes: linear ($i_0 + i$), quadratic ($i_0 + i^2$), and double hashing ($i_0 + i \cdot \text{hash}_2$).
  • Collisions, probing sequences, duplicate key updates, and search hits/misses.
  • Deleted element marking and reuse of earliest deleted index.
  • Dynamic resizing upon crossing load factor threshold.
• Introduced src/algo/__tests__/ClosedHash.test.js:
  • Separate chaining array of pointer heads with linked list nodes.
  • Node collision chaining (inserting multiple colliding keys into same bucket chain).
  • Updating existing keys in-place within bucket chains.
  • Deletions: removing head node, unlinking middle/tail nodes, empty chain checks.
  • Capacity resets and load factor threshold resizing.
• Introduced src/algo/__tests__/NonLinearProbing.test.js:
  • Non-linear probing mathematical equations.
  • Key insertion, collisions, and updates.
  • Deletion with tombstone flags and search traversal.
  • Map filling (fillCallback).

Test Plan

• Ran npm test -- --watchAll=false (all 4 new test suites pass, 36 unit tests passing).
• Ran npm run lint and npm run prettier (0 errors, 0 warnings).