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Testing Bit Extraction Operations in javascript-algorithms

This test suite validates the getBit utility function which extracts individual bits from binary numbers. The tests verify correct bit extraction at different positions using binary representations of decimal numbers. The comprehensive test cases cover various scenarios from simple to complex binary patterns.

Test Coverage Overview

The test suite provides thorough coverage of the getBit function’s core functionality by examining bit extraction across multiple test cases.

Tests bit extraction for numbers 1 (0b0001), 2 (0b0010), 3 (0b0011), and 10 (0b1010)
Verifies correct bit values at different positions (0-3)
Covers edge cases with adjacent 1s and 0s
Tests both least significant and most significant bit positions

Implementation Analysis

The testing approach utilizes Jest’s expect assertions to validate bit extraction results.

Uses toBe() matcher for precise equality checking
Implements multiple assertions within a single test case
Employs binary number representations for clarity
Follows AAA (Arrange-Act-Assert) pattern implicitly

Technical Details

Testing Framework: Jest
Test Type: Unit test
File Structure: Follows __test__ directory convention
Import Strategy: Direct module import
Assertion Style: Expect API

Best Practices Demonstrated

The test implementation showcases several testing best practices for bit manipulation operations.

Clear test descriptions using descriptive it() blocks
Comprehensive test cases with binary number comments
Consistent assertion pattern throughout the test
Logical grouping of related test cases
Self-documenting test structure

trekhleb/javascript-algorithms

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

            
import getBit from '../getBit';

describe('getBit', () => {
  it('should get bit at specific position', () => {
    // 1 = 0b0001
    expect(getBit(1, 0)).toBe(1);
    expect(getBit(1, 1)).toBe(0);

    // 2 = 0b0010
    expect(getBit(2, 0)).toBe(0);
    expect(getBit(2, 1)).toBe(1);

    // 3 = 0b0011
    expect(getBit(3, 0)).toBe(1);
    expect(getBit(3, 1)).toBe(1);

    // 10 = 0b1010
    expect(getBit(10, 0)).toBe(0);
    expect(getBit(10, 1)).toBe(1);
    expect(getBit(10, 2)).toBe(0);
    expect(getBit(10, 3)).toBe(1);
  });
});