public void Hypotense_ReturnsSquareRootOfTheSumOfSquares() { _mockMathService.Setup(x => x.Squared(1)) .Returns(111); _mockMathService.Setup(x => x.Squared(2)) .Returns(222); _mockMathService.Setup(x => x.Add(111, 222)) .Returns(333); _mockMathService.Setup(x => x.SquareRoot(333)) .Returns(444); var expectedResult = 444; var actualResult = _target.Hypotense(1, 2); Assert.AreEqual(expectedResult, actualResult); _mockMathService.Verify(x => x.Squared(1), Times.Once); _mockMathService.Verify(x => x.Squared(2), Times.Once); _mockMathService.Verify(x => x.Add(111, 222), Times.Once); _mockMathService.Verify(x => x.SquareRoot(333), Times.Once); }