using System;

using Xunit;

public class Program

{

    public static void Main()

    {

        // (Optional)Uncomment and use the below line to run your function with any string input you'd like

        // Do NOT use this to manually test your function. That's what your tests are for!

        // Console.WriteLine(new StringCalculator().Add(""));

        StringCalculatorTests.RunAllTests();

    }

}

​

public class StringCalculator

{

    public int Add(string input)

    {

        // Add your code for the solution to each step here (but only after writing a test!)

        return 0;

    }

}

​

​

public static class StringCalculatorTests

{

    public static void RunAllTests()

    {

        Should_Pass_Step_One();

        Console.WriteLine("Test 1 Passed!");

        //Uncomment the below two lines when you are ready to test step 2

        //Should_Pass_Step_Two();

        //Console.WriteLine("Test 2 Passed!");

        //Uncomment the below two lines when you are ready to test step 3

        //Should_Pass_Step_Three();

        //Console.WriteLine("Test 3 Passed!");

        //Uncomment the below two lines when you are ready to test step 4

        //Should_Pass_Step_Four();

        //Console.WriteLine("Test 4 Passed!");

        //Uncomment the below two lines when you are ready to test step 5

        //Should_Pass_Step_Five();

        //Console.WriteLine("Test 5 Passed!");

    }

    public static void Should_Pass_Step_One()

    {

        // Arrange

        var target = new StringCalculator();

        // Act

        var result = target.Add("");

        // Assert

        Assert.Equal(0, result);

    }

    public static void Should_Pass_Step_Two()

    {

        // Write your test for step 2 here

        // Arrange

        // Act

        // Assert

    }

    public static void Should_Pass_Step_Three()

    {

        // Write your test for step 3 here

        // Arrange

        // Act

        // Assert

    }

    public static void Should_Pass_Step_Four()

    {

        // Write your test for step 4 here

        // Arrange

        // Act

        // Assert

    }

    public static void Should_Pass_Step_Five()

    {

        // This test has been completed for you, so that you can observe how you might test that an exception is thrown:

        // Arrange

        var target = new StringCalculator();

        // Act & Assert

        var ex = Assert.Throws<Exception>(() => target.Add("-1+2-3"));

        Assert.Equal("Negative numbers not allowed!", ex.Message);

    }

}