Programming Fundamentals: Getting Started with C# and .NET/

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Unit Testing

Unit Testing

Let's discuss unit testing.

We'll cover the following...

What are unit tests?

Unit tests verify that the logic of code is working as expected. Unit testing breaks a program down into small, testable, individual units.

Why use unit tests?

For example, if we want to test a console-based application that has the following code:

namespace UTCalculator {
    public class CalculatorFeatures
    {
        public static int AddTwoNumbers(int num1, int num2)
        {
            int result = num1 - num2;
            return result; 
        } 
    }
}

Note: We have to test a method named AddTwoNumbers in the class named CalculatorFeature.

If we call this method now, it won’t provide us with the correct output.

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Console.WriteLine(UTCalculator.CalculatorFeatures.AddTwoNumbers(10, 4)); // Output: 6



namespace UTCalculator {

public class CalculatorFeatures

{

    public static int AddTwoNumbers(int num1, int num2)

    {

        int result = num1 - num2;

        return result; }

    } 

}

The code above runs because there are no syntax errors in it. There’s a logic error, however (10 + 4 should equal 14, not 6). A unit test is added to catch this type of error.

How to write a unit test

Use the following steps to write a unit test.

Step 1:

Make a testing directory. In this example, we’re creating a directory named CalculatorTest in the parent directory of UTCalculator ...