calculatorbug-failingtest.ts

export class Calculator {

    public add(firstAddend: number, secondAddend: number): number {
        return firstAddend + secondAddend;
    }

    public subtract(minuend: number, subtrahend: number): number {
        return minuend + subtrahend;
    }

    public multiply(firstFactor: number, secondFactor: number): number {
        return firstFactor * secondFactor;
    }
}


describe('Calculator', () => {
    it('sums up two numbers properly', () => {
        calculator = new Calculator();
        expect(calculator.add(2,2)).to.equal(4);
    });
    // ❌test fails, bug exists
    it('subtracts two numbers properly', () => {
        calculator = new Calculator();
        expect(calculator.subtract(4,2)).to.equal(2);
        expect(calculator.subtract(10,3)).to.equal(7);
        expect(calculator.subtract(-4,2)).to.equal(-6);
        expect(calculator.subtract(-4,-2)).to.equal(-2);
    });

    it('multiplies two numbers properly', () => {
        calculator = new Calculator();
        expect(calculator.subtract(2,2)).to.equal(4);
    });
});