//Test To Verify Add Never Called on the First Term
public void Fibonnaci_GetNthTerm_InputNegative_AssertExceptionThrown()
{
//Arrange
int n = -2;
//setup
Mock <UnitTests.IMath> mockMath = new Mock <UnitTests.IMath>();
mockMath
.Setup(r => r.Add(It.IsAny <int>(), It.IsAny <int>()))
.Returns((int x, int y) => x + y);
UnitTests.Fibonnaci fibonnaci = new UnitTests.Fibonnaci(mockMath.Object);
//Act and Assert
Assert.ThrowsException <System.Exception>(() => fibonnaci.GetNthTerm(n));
}
//Test To Verify Add Called Three times on the fifth Term
public void Fibonnaci_GetNthTerm_Input4_AssertAddCalledThreeTimes()
{
//Arrange
int n = 4;
//setup
Mock <UnitTests.IMath> mockMath = new Mock <UnitTests.IMath>();
mockMath
.Setup(r => r.Add(It.IsAny <int>(), It.IsAny <int>()))
.Returns((int x, int y) => x + y);
UnitTests.Fibonnaci fibonnaci = new UnitTests.Fibonnaci(mockMath.Object);
//Act
int result = fibonnaci.GetNthTerm(n);
//Assert
mockMath.Verify(r => r.Add(It.IsAny <int>(), It.IsAny <int>()), Times.Exactly(3));
}
//Check the Fifth Term To Make the Test More Robust
public void Fibonnaci_GetNthTerm_Input4_AssertResult3()
{
//Arrange
int n = 4;
//setup
Mock <UnitTests.IMath> mockMath = new Mock <UnitTests.IMath>();
mockMath
.Setup(r => r.Add(It.IsAny <int>(), It.IsAny <int>()))
.Returns((int x, int y) => x + y);
UnitTests.Fibonnaci fibonnaci = new UnitTests.Fibonnaci(mockMath.Object);
//Act
int result = fibonnaci.GetNthTerm(n);
//Assert
Assert.AreEqual(result, 3);
}