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C# Unit Testing in C# Test Driven Development TDD

Posted by Larry Singleton
Larry Singleton
18,946 Points

Unit Testing in C#

Link: https://teamtreehouse.com/library/refactor

Question: Challenge Task 1 of 4

Stub out the Calculator class so that the code compiles, but the test cases in CalculatorTests fail as expected.

Calculator.cs is empty

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);
    }
}

I've not added anything because in the videos there is NO reference on how to "Stub Out" anything. I have watched the videos several times and the word and definition is not mentioned. What is meant by "Stub Out"? Please feel free to go in behind me and find there reference if its there. I'm by no means perfect, if it's there, that's on me and I apologize... I'm not finding it and need some direction.

Calculator.cs
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);
    }
}

4 Answers

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

For example, if I was asked to "stub out" a "swim" class that contained a method named "splash" that took a string argument and returned an integer, I might write this:

public class swim
{
    public int splash(string arg)
    {
        return 0;  // temp, needed to compile
    }
}
Larry Singleton
Larry Singleton
18,946 Points
Larry Singleton
Larry Singleton
18,946 Points

Can you please provide an example.

Larry Singleton
Larry Singleton
18,946 Points
Larry Singleton
Larry Singleton
18,946 Points

Thank you

Steven Parker
Steven Parker
229,644 Points
Steven Parker
Steven Parker
229,644 Points

To "stub out" is to create the structure but no contents.

So in this case you'll create the class itself and the methods inside it, but (for the moment) leave the methods empty so they don't do anything.

Any functional tests will fail, of course, but the challenge is expecting that for this task.