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Testing Bitwise Multiplication Implementation in javascript-algorithms

This test suite validates the multiplyByTwo function which performs binary multiplication by two using bitwise operations. The tests verify that the function correctly doubles integer inputs through bit shifting rather than traditional arithmetic multiplication.

Test Coverage Overview

The test coverage focuses on validating the bitwise multiplication operation across different integer values.

Key areas tested include:

Zero value handling
Single digit positive integers
Multi-digit positive integers
Various number ranges from 0 to 125

Implementation Analysis

The testing approach uses Jest’s describe/it pattern to organize test cases in a clear, readable structure. A single test block verifies multiple input-output pairs using expect().toBe() assertions to confirm exact matching results. The implementation leverages Jest’s built-in assertion library for precise equality checking.

Technical Details

Testing infrastructure includes:

Jest testing framework
Bitwise operation validation
Direct function import testing
Synchronous test execution
Equality-based assertions

Best Practices Demonstrated

The test suite exhibits several testing best practices:

Clear test case organization
Comprehensive input range coverage
Descriptive test naming
Efficient test case grouping
Direct and focused test assertions

trekhleb/javascript-algorithms

src/algorithms/math/bits/__test__/multiplyByTwo.test.js

            
import multiplyByTwo from '../multiplyByTwo';

describe('multiplyByTwo', () => {
  it('should multiply numbers by two using bitwise operations', () => {
    expect(multiplyByTwo(0)).toBe(0);
    expect(multiplyByTwo(1)).toBe(2);
    expect(multiplyByTwo(3)).toBe(6);
    expect(multiplyByTwo(10)).toBe(20);
    expect(multiplyByTwo(17)).toBe(34);
    expect(multiplyByTwo(125)).toBe(250);
  });
});