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Testing Factorial Algorithm Implementation in javascript-algorithms

This test suite validates the factorial algorithm implementation using Jest unit tests. The tests verify correct factorial calculations for various input numbers, including edge cases like 0 and 1, as well as larger numbers up to 10.

Test Coverage Overview

The test coverage focuses on validating the factorial function across different input ranges.

Key areas tested include:

Edge case of factorial(0) returning 1
Base case of factorial(1) returning 1
Standard cases with inputs 5, 8, and 10
Verification of larger factorial calculations

Implementation Analysis

The testing approach uses Jest’s describe/it block structure for organized test cases. The implementation leverages Jest’s expect().toBe() matcher for precise equality assertions, ensuring accurate factorial calculations across all test cases.

The tests follow a progressive complexity pattern, starting with edge cases and moving to larger numbers.

Technical Details

Testing tools and setup:

Jest as the primary testing framework
ES6 import/export syntax for module handling
Describe/It blocks for test organization
Expect assertions for result validation

Best Practices Demonstrated

The test suite exemplifies several testing best practices in mathematical algorithm validation.

Notable practices include:

Clear test case organization
Coverage of edge cases (0,1)
Progressive complexity testing
Concise and focused test descriptions
Efficient use of multiple assertions within a single test block

trekhleb/javascript-algorithms

src/algorithms/math/factorial/__test__/factorial.test.js

            
import factorial from '../factorial';

describe('factorial', () => {
  it('should calculate factorial', () => {
    expect(factorial(0)).toBe(1);
    expect(factorial(1)).toBe(1);
    expect(factorial(5)).toBe(120);
    expect(factorial(8)).toBe(40320);
    expect(factorial(10)).toBe(3628800);
  });
});