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Testing Square Matrix Rotation Algorithm in javascript-algorithms

This test suite validates the in-place rotation functionality of square matrices, ensuring correct 90-degree clockwise rotation for matrices of different sizes. The tests verify matrix transformation while maintaining data integrity and proper element positioning.

Test Coverage Overview

The test suite provides comprehensive coverage of square matrix rotation scenarios.

Key areas tested include:

Single element matrix rotation
2×2 matrix transformation
3×3 matrix rotation validation
4×4 larger matrix handling

Edge cases are addressed through testing of minimal (1×1) and larger matrices, ensuring the algorithm works across different dimensions.

Implementation Analysis

The testing approach employs Jest’s expect().toEqual() matcher for precise matrix comparison. Each test case follows a consistent pattern of defining input matrix, expected output, and validation, demonstrating clean testing practices.

Technical implementation features:

In-place rotation verification
Matrix structure preservation
Element position validation
Nested array comparison

Technical Details

Testing infrastructure includes:

Jest testing framework
Array manipulation validation
Deep equality comparison
Modular test organization

Configuration maintains isolation between test cases while ensuring consistent matrix transformation validation.

Best Practices Demonstrated

The test suite exemplifies strong testing practices through clear test case organization and comprehensive coverage. Notable practices include:

Descriptive test case naming
Consistent test structure
Progressive complexity testing
Clear input/output expectations
Isolated test cases

trekhleb/javascript-algorithms

src/algorithms/uncategorized/square-matrix-rotation/__test__/squareMatrixRotation.test.js

            
import squareMatrixRotation from '../squareMatrixRotation';

describe('squareMatrixRotation', () => {
  it('should rotate matrix #0 in-place', () => {
    const matrix = [[1]];

    const rotatedMatrix = [[1]];

    expect(squareMatrixRotation(matrix)).toEqual(rotatedMatrix);
  });

  it('should rotate matrix #1 in-place', () => {
    const matrix = [
      [1, 2],
      [3, 4],
    ];

    const rotatedMatrix = [
      [3, 1],
      [4, 2],
    ];

    expect(squareMatrixRotation(matrix)).toEqual(rotatedMatrix);
  });

  it('should rotate matrix #2 in-place', () => {
    const matrix = [
      [1, 2, 3],
      [4, 5, 6],
      [7, 8, 9],
    ];

    const rotatedMatrix = [
      [7, 4, 1],
      [8, 5, 2],
      [9, 6, 3],
    ];

    expect(squareMatrixRotation(matrix)).toEqual(rotatedMatrix);
  });

  it('should rotate matrix #3 in-place', () => {
    const matrix = [
      [5, 1, 9, 11],
      [2, 4, 8, 10],
      [13, 3, 6, 7],
      [15, 14, 12, 16],
    ];

    const rotatedMatrix = [
      [15, 13, 2, 5],
      [14, 3, 4, 1],
      [12, 6, 8, 9],
      [16, 7, 10, 11],
    ];

    expect(squareMatrixRotation(matrix)).toEqual(rotatedMatrix);
  });
});