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Testing Interpolation Search Algorithm Implementation in javascript-algorithms

This test suite validates the implementation of interpolation search algorithm in JavaScript, focusing on searching elements in sorted numerical arrays. The tests verify the algorithm’s behavior across various array sizes and element distributions.

Test Coverage Overview

The test suite provides comprehensive coverage of interpolation search functionality with multiple test cases.

Key areas tested include:

Empty array handling
Single element arrays
Arrays with duplicate values
Large sorted arrays with varying distributions
Edge cases for first/last elements
Non-existent element searches

Implementation Analysis

The testing approach utilizes Jest’s describe/it pattern for structured test organization. Each test case employs expect().toBe() assertions to verify exact index matching for search results.

The implementation tests both sequential and distributed number arrays, ensuring the interpolation search algorithm maintains efficiency across different data distributions.

Technical Details

Testing Framework: Jest
Test Structure: Single describe block with multiple test cases
Assertion Style: Explicit equality checking
File Organization: Separate test file with imported algorithm module

Key components:

Array input validation
Index return verification
Boundary condition testing

Best Practices Demonstrated

The test suite exemplifies several testing best practices including comprehensive edge case coverage and clear test case organization.

Notable practices:

Systematic test case progression from simple to complex scenarios
Consistent assertion pattern usage
Thorough boundary testing
Clear test case separation and readability

trekhleb/javascript-algorithms

src/algorithms/search/interpolation-search/__test__/interpolationSearch.test.js

            
import interpolationSearch from '../interpolationSearch';

describe('interpolationSearch', () => {
  it('should search elements in sorted array of numbers', () => {
    expect(interpolationSearch([], 1)).toBe(-1);
    expect(interpolationSearch([1], 1)).toBe(0);
    expect(interpolationSearch([1], 0)).toBe(-1);
    expect(interpolationSearch([1, 1], 1)).toBe(0);
    expect(interpolationSearch([1, 2], 1)).toBe(0);
    expect(interpolationSearch([1, 2], 2)).toBe(1);
    expect(interpolationSearch([10, 20, 30, 40, 50], 40)).toBe(3);
    expect(interpolationSearch([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 14)).toBe(13);
    expect(interpolationSearch([1, 6, 7, 8, 12, 13, 14, 19, 21, 23, 24, 24, 24, 300], 24)).toBe(10);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 600)).toBe(-1);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 1)).toBe(0);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 2)).toBe(1);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 3)).toBe(2);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 700)).toBe(3);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 800)).toBe(4);
    expect(interpolationSearch([0, 2, 3, 700, 800, 1200, 1300, 1400, 1900], 1200)).toBe(5);
    expect(interpolationSearch([1, 2, 3, 700, 800, 1200, 1300, 1400, 19000], 800)).toBe(4);
    expect(interpolationSearch([0, 10, 11, 12, 13, 14, 15], 10)).toBe(1);
  });
});