public void ShouldMulTwoNumbers()
 {
     ICalculator sut = new Calculator();
     int expectedResult = sut.Mul(7, 8);
     Assert.That(expectedResult, Is.EqualTo(56));
 }
 public void ShouldSqOneNumber()
 {
     ICalculator sut = new Calculator();
     int expectedResult = sut.Sq(7);
     Assert.That(expectedResult, Is.EqualTo(49));
 }
 public void ShouldAddTwoNumbers()
 {
     ICalculator sut = new Calculator();
     int expectedResult = sut.Add(7, 8);
     Assert.That(expectedResult, Is.EqualTo(15));
 }