import { describe, it } from 'mocha';
import { expect } from 'chai';
describe('Calculator Module', () => {
describe('Safe Evaluation Function', () => {
// We'll test the calculator functionality through a simple function
function safeEval(expression) {
// Remove any whitespace
const cleanExpression = expression.replace(/\s+/g, '');
// Validate that the expression only contains allowed characters
const allowedPattern = /^[0-9+\-*/.()%\s]+$/;
if (!allowedPattern.test(cleanExpression)) {
throw new Error(
'Invalid characters in expression. Only numbers, +, -, *, /, %, ., (, ) are allowed.'
);
}
// Check for potential security issues
if (
cleanExpression.includes('__') ||
cleanExpression.includes('constructor') ||
cleanExpression.includes('prototype')
) {
throw new Error('Invalid expression detected.');
}
try {
// Use Function constructor for safer evaluation than eval()
const result = new Function('return ' + cleanExpression)();
if (typeof result !== 'number' || !isFinite(result)) {
throw new Error('Expression did not evaluate to a valid number.');
}
return result;
} catch (error) {
throw new Error(`Calculation error: ${error.message}`);
}
}
it('should perform basic addition', () => {
const result = safeEval('2 + 3');
expect(result).to.equal(5);
});
it('should perform basic subtraction', () => {
const result = safeEval('10 - 4');
expect(result).to.equal(6);
});
it('should perform basic multiplication', () => {
const result = safeEval('3 * 7');
expect(result).to.equal(21);
});
it('should perform basic division', () => {
const result = safeEval('15 / 3');
expect(result).to.equal(5);
});
it('should handle modulo operation', () => {
const result = safeEval('10 % 3');
expect(result).to.equal(1);
});
it('should handle parentheses', () => {
const result = safeEval('(2 + 3) * 4');
expect(result).to.equal(20);
});
it('should handle decimal numbers', () => {
const result = safeEval('3.14 * 2');
expect(result).to.be.closeTo(6.28, 0.001);
});
it('should handle complex expressions', () => {
const result = safeEval('2 + 3 * 4 - (10 / 2)');
expect(result).to.equal(9);
});
it('should throw error for invalid characters', () => {
expect(() => safeEval('2 + eval("alert(1)")')).to.throw('Invalid characters');
});
it('should throw error for security patterns', () => {
expect(() => safeEval('2 + constructor')).to.throw('Invalid characters');
});
it('should throw error for malformed expressions', () => {
expect(() => safeEval('2 + + 3')).to.throw('Calculation error');
});
it('should handle division by zero', () => {
expect(() => safeEval('5 / 0')).to.throw('Expression did not evaluate to a valid number');
});
it('should handle expressions with whitespace', () => {
const result = safeEval(' 2 + 3 * 4 ');
expect(result).to.equal(14);
});
});
describe('Module Structure', () => {
it('should export the required functions', async () => {
const module = await import('../index.js');
expect(module.register).to.be.a('function');
expect(module.unregister).to.be.a('function');
expect(module.metadata).to.be.an('object');
});
it('should have correct metadata', async () => {
const { metadata } = await import('../index.js');
expect(metadata.name).to.equal('Calculator Module');
expect(metadata.version).to.equal('1.0.0');
expect(metadata.description).to.include('mathematical operations');
expect(metadata.author).to.equal('Profullstack, Inc.');
expect(metadata.tools).to.include('calculator');
expect(metadata.endpoints).to.be.an('array');
expect(metadata.endpoints.length).to.be.greaterThan(0);
});
});
});
