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Testing Hamming Distance String Comparison in javascript-algorithms

This test suite validates the Hamming Distance algorithm implementation in JavaScript, ensuring accurate calculation of differences between two strings. The tests verify both error handling for invalid inputs and correct distance calculations across various string pairs.

Test Coverage Overview

The test suite provides comprehensive coverage of the Hamming Distance calculation functionality.

Key areas tested include:

Error handling for strings of different lengths
Zero distance for identical strings
Single character differences
Multiple character differences
Both alphabetic and numeric string comparisons

Implementation Analysis

The testing approach utilizes Jest’s describe/it pattern for clear test organization. The implementation employs both error validation and functional testing patterns.

Framework-specific features include:

Jest’s toThrowError() for exception testing
toBe() matcher for exact equality assertions
Multiple test cases within single it blocks for efficiency

Technical Details

Testing infrastructure includes:

Jest as the primary testing framework
ES6 module import syntax
Function-level unit testing
Error boundary testing
Multiple assertion patterns

Best Practices Demonstrated

The test suite exemplifies several testing best practices.

Notable elements include:

Separate test cases for error conditions and normal operation
Comprehensive edge case coverage
Clear test descriptions
Consistent assertion patterns
Efficient test organization with grouped assertions

trekhleb/javascript-algorithms

src/algorithms/string/hamming-distance/__test__/hammingDistance.test.js

            
import hammingDistance from '../hammingDistance';

describe('hammingDistance', () => {
  it('should throw an error when trying to compare the strings of different lengths', () => {
    const compareStringsOfDifferentLength = () => {
      hammingDistance('a', 'aa');
    };

    expect(compareStringsOfDifferentLength).toThrowError();
  });

  it('should calculate difference between two strings', () => {
    expect(hammingDistance('a', 'a')).toBe(0);
    expect(hammingDistance('a', 'b')).toBe(1);
    expect(hammingDistance('abc', 'add')).toBe(2);
    expect(hammingDistance('karolin', 'kathrin')).toBe(3);
    expect(hammingDistance('karolin', 'kerstin')).toBe(3);
    expect(hammingDistance('1011101', '1001001')).toBe(2);
    expect(hammingDistance('2173896', '2233796')).toBe(3);
  });
});