Back to Repositories

Testing QuickSort Algorithm Implementation in javascript-algorithms

This test suite validates the QuickSort algorithm implementation, focusing on sorting functionality, performance characteristics, and edge cases. The tests verify both basic sorting capabilities and specific behavioral aspects like stability and handling of negative numbers.

Test Coverage Overview

The test suite provides comprehensive coverage of QuickSort functionality:

Basic array sorting validation
Custom comparator testing
Sorting stability verification
Negative number handling
Time complexity validation across different array types (equal, sorted, unsorted, reverse sorted)

Implementation Analysis

The testing approach utilizes Jest’s describe/it pattern for structured test organization. The implementation leverages a shared SortTester utility for consistent validation across different array scenarios and sorting conditions. Time complexity is verified through visit count assertions for different array states.

Technical Details

Testing tools and configuration:

Jest testing framework
SortTester utility for standardized sort validation
Complexity constants for performance benchmarking
Custom array fixtures (equalArr, notSortedArr, reverseArr, sortedArr)

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Modular test organization
Consistent complexity validation
Comprehensive edge case coverage
Reusable test utilities
Clear test case isolation and naming

trekhleb/javascript-algorithms

src/algorithms/sorting/quick-sort/__test__/QuickSort.test.js

            
import QuickSort from '../QuickSort';
import {
  equalArr,
  notSortedArr,
  reverseArr,
  sortedArr,
  SortTester,
} from '../../SortTester';

// Complexity constants.
const SORTED_ARRAY_VISITING_COUNT = 190;
const NOT_SORTED_ARRAY_VISITING_COUNT = 62;
const REVERSE_SORTED_ARRAY_VISITING_COUNT = 190;
const EQUAL_ARRAY_VISITING_COUNT = 19;

describe('QuickSort', () => {
  it('should sort array', () => {
    SortTester.testSort(QuickSort);
  });

  it('should sort array with custom comparator', () => {
    SortTester.testSortWithCustomComparator(QuickSort);
  });

  it('should do stable sorting', () => {
    SortTester.testSortStability(QuickSort);
  });

  it('should sort negative numbers', () => {
    SortTester.testNegativeNumbersSort(QuickSort);
  });

  it('should visit EQUAL array element specified number of times', () => {
    SortTester.testAlgorithmTimeComplexity(
      QuickSort,
      equalArr,
      EQUAL_ARRAY_VISITING_COUNT,
    );
  });

  it('should visit SORTED array element specified number of times', () => {
    SortTester.testAlgorithmTimeComplexity(
      QuickSort,
      sortedArr,
      SORTED_ARRAY_VISITING_COUNT,
    );
  });

  it('should visit NOT SORTED array element specified number of times', () => {
    SortTester.testAlgorithmTimeComplexity(
      QuickSort,
      notSortedArr,
      NOT_SORTED_ARRAY_VISITING_COUNT,
    );
  });

  it('should visit REVERSE SORTED array element specified number of times', () => {
    SortTester.testAlgorithmTimeComplexity(
      QuickSort,
      reverseArr,
      REVERSE_SORTED_ARRAY_VISITING_COUNT,
    );
  });
});