public void TestThatTenGenerosityReturnsTenPercentTip()
        {
            // Arrange
            var tip = new TipService();

            // Act
            var result = tip.Calc(42.35, 10);

            // Assert
            Assert.AreEqual(4.235, result);
        }
        public void TestThatZeroGenerosityReturnsZeroTip()
        {
            // Arrange
            var tip = new TipService();

            // Act
            var result = tip.Calc(42.35, 0);

            // Assert
            Assert.AreEqual(0, result);
        }