This contains a Test Driven Development (TDD) demo for Copilot for C# and .NET through Visual Studio IDE. This is going to be useful for customers who are interested in using Copilot for C# and .NET and want to use Copilot to generate code through Visual Studio IDE.
Note that Copilot extension for Visual Studio IDE is only available for Windows. If you are using Mac, you can use Copilot through VS Code.
Test-Driven Development (TDD) is a software develpment proces relying on software requirements being converted to test cases before software is fully developed. Since unit testing or any type of functional or performance testings are very important in programming development, TDD practice is very highly encouraged among C# and.NET developers. Copilot is a great tool to help C# and .NET developers to write unit tests for their C# and .NET code as it can helps to bootstrap a lot of repetitive code for unit tests.
As you can see in the picture below, TDD process involves writing tests first, see if it fails (goes to red), then write code to make the test pass (green). Copilot can help you to write the test code and you can focus on writing the code to make the test pass.
This demo is focusing around how to use Copilot to easily write unit tests for C# and .NET code. We will be using Visual Studio IDEA for this demo.
- C#
- Visual Studio IDE for Windows
This guide will walk you through the steps to get started with Copilot in Visual Studio IDE.
Make sure that you meet the following requirements.
- Visual Studio IDE for Windows
- Copilot Extension for Visual Studio IDE.
See this documentation on how to install Copilot extension for Visual Studio IDE
In your Windows, click bottom left's Windows button, then search for Visual Studio. Select Visual Studio IDE installed with Copilot.
You can then select an existing project if you followed previous Getting Started guide. Or, you can create a new projet if you don't have one.
Once your Visual Studio IDE is opened, you need to add a new project. From top, click File then select Add. Click New Project....
From there, search for test. You will see Unit Test Project shows up, so select that.
Give your unit testing project some name. In my case, I named TestWithCopilot. This is going to be my namespace for this project.
Once your new unit test project is created. Verify following things:
- Make sure that your GitHub Copilot is running as seen in the Output window
- Your
namespaceshows what you give as your Project name - You can see two projects under Solution Explorer window
Although it is an optional step, we will try to rename our unit testing file and its class. I renmaed mine to CopilotTest
I also need to make a change to my file. On Solutions Explorer window, select the file to rename.
Once it is done, it shoudld look something like this.
Our unit testing project is dependent on our other project (e.g. HelloCopilot). Thus, we need to add a dependency.
Make sure that you select your unit testing project under Solution Explorer.
Then, we need to make following two changes. First, select Project under top tool menu. Under a new dropdown menu, scroll down to select Project Dependencies....
Then, check your source code project and click OK to save.
Next, we need to add our source code project as a reference to our unit testing project. To do that, select Project under tool menu again. But this time, select Add Reference....
Then, click Projects followed by Solution. You should see your source code project, so select that. Click OK button to save.
Let's build project. On top menu tool bar, click Build then select Build Solution.
This should print out a message like this under Output window.
We are finally ready to implement our unit test in TDD style. But first, add the following line in your unit testing class. You need to add your source code project namespace with using keyword. For example, in my example below, I added using HelloCopilot because HelloCopilot is my namespace for my source code project.
You will notice that it generates a sample test method. As you try to type in it, Copilot might generate some test method as you see above.
But there is one change that we definitely need to make before running this, especially if you followed previous Getting Started example. In your source code class, change that visibility of class from internal to public.
Now, we are ready to write actual unit test!
We could use existing method, but we will just write a new unit test from scratch. Just rename your function to something like AddTwoNumbersEqualsCorrect. Then, Copilot will try to generate a test method with a function that does not yet exist.
Let's go to our source code class. As you click under class, you should that Copilot will try to generate suggestion like this based on the method you added in your test class.
Let's accept that suggestion. Next, let's try to build. Click Build under tool bar, then select Build Solution.
Next, let's try to run unit test. Click Test under tool bar, and select Run All Tests.
This will bring a pop up window showing that your test is successful. Congratulation! You just wrote a TDD style unit test through C# and .NET.
You can try to add more unit test like this. For example, Copilot automatically suggests some failure scenario for me.
Of course, if you accept the suggestion, it will look like this. But feel free to add your own unit test.
And this is the result after running our second test.
After this, you can add some more custom example using String, sorting function, etc. But as you can see, Copilot can help you eaisly adopt Test Driven Development (TDD) in an easy way as possible. Or, should we say Copilot Driven Development?
Contributions are warmly welcomed! ✨
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