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Testing Linked List Reverse Traversal in javascript-algorithms

This test suite validates the reverse traversal functionality of a linked list implementation in JavaScript. It ensures that nodes can be visited in reverse order while maintaining data integrity and proper callback execution.

Test Coverage Overview

The test coverage focuses on validating reverse traversal operations on a linked list data structure.

Key aspects tested include:

Correct reverse order traversal of nodes
Proper callback execution for each node
Verification of node values in reverse sequence

Implementation Analysis

The testing approach utilizes Jest’s describe/it pattern for organizing test cases. The implementation leverages callback functions to process node values during traversal, demonstrating both functional and structural testing patterns.

Notable patterns include:

Callback-based value collection
Sequential node value verification
Array-based result validation

Technical Details

Testing infrastructure includes:

Jest testing framework
LinkedList data structure implementation
Custom reverseTraversal function
Array-based result verification

Best Practices Demonstrated

The test suite exhibits several testing best practices for data structure validation.

Notable practices include:

Clear test case isolation
Explicit expected value assertions
Modular test structure
Comprehensive setup and teardown

trekhleb/javascript-algorithms

src/algorithms/linked-list/reverse-traversal/__test__/reverseTraversal.test.js

            
import LinkedList from '../../../../data-structures/linked-list/LinkedList';
import reverseTraversal from '../reverseTraversal';

describe('reverseTraversal', () => {
  it('should traverse linked list in reverse order', () => {
    const linkedList = new LinkedList();

    linkedList
      .append(1)
      .append(2)
      .append(3);

    const traversedNodeValues = [];
    const traversalCallback = (nodeValue) => {
      traversedNodeValues.push(nodeValue);
    };

    reverseTraversal(linkedList, traversalCallback);

    expect(traversedNodeValues).toEqual([3, 2, 1]);
  });
});

// it('should reverse traversal the linked list with callback', () => {
//   const linkedList = new LinkedList();
//
//   linkedList
//     .append(1)
//     .append(2)
//     .append(3);
//
//   expect(linkedList.toString()).toBe('1,2,3');
//   expect(linkedList.reverseTraversal(linkedList.head, value => value * 2)).toEqual([6, 4, 2]);
//   expect(() => linkedList.reverseTraversal(linkedList.head)).toThrow();
// });