You can use Visual Studio to create projects; however, in this post, I will use .NET Core commands to create my projects, add tests, and run tests. You can also use MSTest or NUnit to write unit tests, but in this example, I\u2019ll use xUnit and dotnet test to write and run my Unit Tests.<\/p>\n\n\n\n
Let\u2019s start by opening a command shell and follow along: <\/p>\n\n\n\n
Creating the Application Project<\/h2>\n\n\n\n
To start, you\u2019ll need to create a directory called CalculatorApp<\/b>. Keep in mind that you can follow any naming convention you\u2019d like for directories, but if you\u2019d like to follow along with this post, I would recommend following the same directory name. So, let\u2019s create the CalculatorApp directory and navigate to it.<\/p>\n\n\n\n
Inside the CalculatorApp directory, we are going to create a new solution by running the following command:<\/p>\n\n\n\n
dotnet new sln<\/h3>\n\n\n\n
After successfully running the command, you should get the message \u201cThe Template Solution File was created successfully\u201d. Also inside the CalculatorApp directory, you will find a file named calculatorapp.sln.<\/p>\n\n\n\n
Next, create a directory called CalculatorApp.Services. <\/b>This directory will keep the application sources i.e. all classes of the calculator application. Navigate to the Calculatorapp.Services directory and create a class library by running the following command:<\/p>\n\n\n\ndotnet new classlib<\/h3>\n\n\n\n
After successfully running this command, you should get the message \u201cThe Template Class Library was created successfully\u201d. You\u2019ll also find a file named calculatorapp.services.csproj inside the CalculatorApp.Services directory. Next, you need to add this class library project to the calculatorapp solution. To do this, navigate back to the calculatorapp directory, and run the command:<\/p>\n\n\n\n
dotnet sln add .\\calculatorapp.services\\calculatorapp.services.csproj<\/h3>\n\n\n\n
After successfully running the command, you should get the message \u201cProject added to the solution\u201d.<\/p>\n\n\n\n
Inside the CalculatorApp.Services folder, you will find a class Class1<\/b> – rename it to Calculator<\/b> and modify the class as shown in the listing below: <\/p>\n\n\n\n
Calculator.cs<\/span><\/b><\/p>\n\n\n\n You\u2019ll notice in the above listing that the Add and Sub functions are not implemented. First, we will write a unit test and then implement these functionalities. <\/p>\n\n\n\n To add test projects, create a directory called CalculatorApp.Services.Tests and navigate to the directory. In this directory, we will create an MS Test project by running the following command:<\/p>\n\n\n\n This command creates the test project which uses MS Test as the test library. Once the test project is created, add the source project library in the test project. To do that, run the command:<\/p>\n\n\n\n <\/b>This <\/b>command will add a reference of the CalculatorAppService project into the test project. After adding the reference, add the test project to the solution by navigating to the calculatorapp root directory, and run the command:<\/p>\n\n\n\n This command will add the test project to the solution. After successfully running the command, you should get the message \u201cProject added to the solution\u201d. <\/p>\n\n\n\n So far, we\u2019ve created the application source project and a test project. In the application source project, there are unimplemented functions. Now let us write tests for these functions.<\/p>\n\n\n\n In the Test project, I have renamed the file UnitTest1.cs to Calculator.Test.cs and the class name to CalculatorTest. In the constructor of CalculatorTest, we need to create an object of the Calculator class. This can be done as shown in the listing below: <\/p>\n\n\n\n Calculator.Test.cs<\/span><\/b><\/p>\n\n\n\n In the CalculatorTest class, add a unit test method to test the add functionality as shown in the listing below: <\/p>\n\n\n\n To run the test, navigate to the CalculatorApp.Services.Tests directory and execute the command:<\/p>\n\n\n\n You\u2019ll get a \u2018test failed\u2019 output because the Add function is not implemented, as shown in the image below:<\/p>\n\n\n\n To pass the test, implement the Add function in the Calculator class as shown in the listing below:<\/p>\n\n\n\n To run the test now, navigate to the CalculatorApp.Services.Tests director and execute the command:<\/p>\n\n\n\n As output, you will get the \u2018test passed\u2019 message as shown in the image below:<\/p>\n\n\n\n Now you have implemented the Add functionality while adhering to the TDD approach in a .NET Core application!<\/p>\n\n\n\n In the CalculatorTest class, add a unit test method to test the sub functionality as shown in the listing below: <\/p>\n\n\n\n To run the test, navigate to the CalculatorApp.Services.Tests directory and execute the command:<\/p>\n\n\n\n Here, your test will fail because the Sub function is not implemented. You will get one failed test result as shown in the image below:<\/p>\n\n\n\n To pass the test, implement the Sub function in the Calculator class as shown in the below listing:<\/p>\n\n\n\n Now run the test again by navigating to the CalculatorApp.Services.Tests directory and executing:<\/p>\n\n\n\n Now you\u2019ll find both tests passed, as seen here:<\/p>\n\n\n\n Now you have implemented Sub functionality while adhering to the TDD approach in a .NET Core application.<\/p>\n\n\n\n So far in this post, we\u2019ve created a .NET Core Calculator application while adhering to the TDD approach. To create tests, we used the XUnit and dotnet tests. For your reference, here is the source code of both the Calculator class and its test class:<\/p>\n\n\n\n Calculator.cs<\/span><\/b><\/p>\n\n\n\n Calculator.test.cs<\/span><\/b><\/p>\n\n\n\nusing System;\nnamespace calculatorapp.services {\n public class Calculator {\n public int Add(int num1, int num2) {\n throw new NotImplementedException();\n }\n public int Sub(int num1, int num2) {\n throw new NotImplementedException();\n }\n }\n}<\/pre>\n\n\n\nCreating the Test Project<\/h3>\n\n\n\n
dotnet new mstest<\/h3>\n\n\n\n
dotnet add reference ..\/CalculatorApp.Services\/CalculatorApp.Services.csproj<\/h4>\n\n\n\n
dotnet sln add .\\CalculatorAppServices.tests\\CalculatorAppServices.Tests.csproj<\/h3>\n\n\n\n
Writing Unit Tests<\/h2>\n\n\n\n
using Microsoft.VisualStudio.TestTools.UnitTesting;\nusing calculatorapp.services;\nnamespace CalculatorApp.Services.Tests {\n [TestClass]\n public class CalculatorTest {\n Calculator _calc;\n public CalculatorTest() {\n _calc = new Calculator();\n }\n }\n}<\/pre>\n\n\n\nUnit Test For Add Function<\/h3>\n\n\n\n
[TestMethod]\npublic void shouldaddtwonumbers() {\n int res = _calc.Add(5, 3);\n Assert.AreEqual(res, 8);\n}<\/pre>\n\n\n\ndotnet test <\/h3>\n\n\n\n
![\"\"](\"https:\/\/staging.infragistics.com\/blogs\/wp-content\/uploads\/2017\/11\/image.png\")
<\/figure>\n\n\n\npublic int Add(int num1, int num2) {\n int result = num1 + num2;\n return result;\n}<\/pre>\n\n\n\ndotnet test <\/h3>\n\n\n\n
![\"\"](\"https:\/\/staging.infragistics.com\/blogs\/wp-content\/uploads\/2017\/11\/image-1.png\")
<\/figure>\n\n\n\nUnit Test For Sub Function<\/h3>\n\n\n\n
[TestMethod]\npublic void shouldsubstracttwonumbers() {\n int res = _calc.Sub(5, 3);\n Assert.AreEqual(res, 2);\n}<\/pre>\n\n\n\ndotnet test <\/h3>\n\n\n\n
![\"\"](\"https:\/\/staging.infragistics.com\/blogs\/wp-content\/uploads\/2017\/11\/image-2.png\")
<\/figure>\n\n\n\npublic int Sub(int num1, int num2) {\n int result = num1 - num2;\n return result;\n}<\/pre>\n\n\n\ndotnet test<\/h3>\n\n\n\n
![\"\"](\"https:\/\/staging.infragistics.com\/blogs\/wp-content\/uploads\/2017\/11\/image-3.png\")
<\/figure>\n\n\n\nWrapping Up<\/h2>\n\n\n\n
using System;\nnamespace calculatorapp.services {\n public class Calculator {\n public int Add(int num1, int num2) {\n int result = num1 + num2;\n return result;\n }\n public int Sub(int num1, int num2) {\n int result = num1 - num2;\n return result;\n }\n }\n}<\/pre>\n\n\n\nusing Microsoft.VisualStudio.TestTools.UnitTesting;\nusing calculatorapp.services;\nnamespace CalculatorApp.Services.Tests {\n [TestClass]\n public class CalculatorTest {\n Calculator _calc;\n public CalculatorTest() {\n _calc = new Calculator();\n }\n [TestMethod]\n public void shouldaddtwonumbers() {\n int res = _calc.Add(5, 3);\n Assert.AreEqual(res, 8);\n }\n [TestMethod]\n public void shouldsubstracttwonumbers() {\n int res = _calc.Sub(5, 3);\n Assert.AreEqual(res, 2);\n }\n }\n}<\/pre>\n\n\n\n
![\"](\"https:\/\/download.infragistics.com\/marketing\/Blog-in-content-ads\/Ignite-UI-JavaScript\/Blog-incontent-IgniteUI-650x200.jpg\")
<\/a><\/figure>\n\n\n\n