C# Unit Testing in C# Test Driven Development TDD

I don't know why I'm getting this error on Task 1 of 4 of TDD section of C# Unit Testing course

I'm supposed to "Stub out the Calculator class so that the code compiles, but the test cases in CalculatorTests fail as expected." I'm getting the following error: "CalculatorTests.cs(18,16): error CS1061: Type Calculator' does not contain a definition forAdd' and no extension method Add' of typeCalculator' could be found. Are you missing an assembly reference? Calculator.cs(3,14): (Location of the symbol related to previous error)." It is referring to the line in CalculatorTests.cs where it says target.Add.
I barely understand what I'm doing, so this error has me at a complete loss for what to do.

Calculator.cs
using System;

public class Calculator
{

    public double Result;

    public Calculator(double value)
    {
        Result = value;
    }

    public void Initialization()
    {

    }

    public double BasicAdd(double value)
    {
       return Result += value;
    }
}
CalculatorTests.cs
using Xunit;


public class CalculatorTests
{
    [Fact]
    public void Initialization()
    {
        var expected = 1.1;
        var target = new Calculator(1.1);
        Assert.Equal(expected, target.Result, 1);
    }

    [Fact]
    public void BasicAdd()
    {
        var target = new Calculator(1.1);
        target.Add(2.2);
        var expected = 3.3;
        Assert.Equal(expected, target.Result, 1);
    }
}

1 Answer

Nevermind. I figured it out