Mock HttpClient Using Moq

In this Post we are going to see how to mock the HttpClient using HttpMessageHandler in Moq. For this first we will create sample console app, which retrieves the data from RestApi call.

namespace TestCaseApp

{

    public class Post

    {

        public int userId { set; get; }

        public int id { set; get; }

        public string title { set; get; }

        public string body { set; get; }

    }

}

Above class is a model class

namespace TestCaseApp

{

    public interface IPostUtility

    {

       Task<Post> GetData();

    }

}

From the below method you may see that we are consuming a rest api using Httpclient

namespace TestCaseApp

{

    public class PostUtility: IPostUtility

    {

        HttpClient _client;

        public PostUtility()

        {

        }

        public PostUtility(HttpClient client)

        {

            _client = client;

        }

        public async Task<Post> GetData()

        {

            using (var client = _client ?? new HttpClient())

            {

                HttpResponseMessage response = await client.GetAsync("https://jsonplaceholder.typicode.com/posts/1");

                response.EnsureSuccessStatusCode();

                using (HttpContent content = response.Content)

                {

                    string responseBody = await response.Content.ReadAsStringAsync();                   

                    var articles = JsonConvert.DeserializeObject<Post>(responseBody);

                    return articles;

                }

            }

        }

    }

}

Main.cs

************

class Program

    {

        static void Main(string[] args)

        {

            IPostUtility post = new PostUtility();

            var _post =  post.GetData();

            _post.Wait();

            var result = _post.Result;

            Console.WriteLine($" Id: {result.id}, body: {result.body}");

            Console.ReadLine();

        }      

    }

output:

***********

Id: 1, body: quia et suscipit

Above main method is the calling part , where we can see the result of Post Data. Now are going to write a moq for this method and mock the HttpClient

To Mock the HttpClient we need to use HttpMessageHandler class, mock this class and pass this is in constructor of HttpClient.

Test Method:

***************

using System;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using TestCaseApp;

using System.Net.Http;

using Moq;

using Moq.Protected;

using System.Threading.Tasks;

using System.Threading;

namespace TestCaseAppTests

{

    [TestClass]

    public class PostUtilityTests

    {

        private IPostUtility _postUtility;

        private Mock<HttpMessageHandler> _mockHttpMessageHandler;

        [TestInitialize]

        public void Initialize()

        {

            _mockHttpMessageHandler = new Mock<HttpMessageHandler>();

            _postUtility = new PostUtility(new HttpClient(_mockHttpMessageHandler.Object));

        }

        [TestMethod]

        public void GetPostData()

        {

            // Arrange          

            _mockHttpMessageHandler.Protected().Setup<Task<HttpResponseMessage>>("SendAsync",

                ItExpr.IsAny<HttpRequestMessage>(),

                ItExpr.IsAny<CancellationToken>())

                .Returns(Task.FromResult(new HttpResponseMessage() {

                    StatusCode = System.Net.HttpStatusCode.OK,Content =new StringContent(PostString())

                }));

            // Act

            var _result = _postUtility.GetData();

            _result.Wait();

            var data = _result.Result;

            // Assert

            Assert.AreEqual(data.body, "sample");

           

        }

        private string PostString()

        {

            return "{\"userId\": 1,\"id\": 1,\"title\": \"rajTitle\",\n  \"body\": \"sample\"}";

        }

    }

}

From this post you can learn how to mock the HttpClient using the  HttpMessageHandler in Moq

Create a Unit Test Case in C# using Moq

In this post we are going to see how to create a unit test case in C# using Moq. First we create a library project and write the following code.

public interface ICalculator

    {

       (string operation, int result) DoOperation(string operation, int a, int b);

    }

    public class Calculator:ICalculator

    {

        public (string operation,int result) DoOperation(string operation,int a,int b)

        {

            (string operation, int result) operationResult;

            int c = 0;

            switch (operation)

            {

                case "add":

                    c = a + b;

                    break;

                case "sub":

                    c = a - b;

                    break;

                case "mul":

                    c = a * b;

                    break;

                default:

                    c = a + b;

                    break;

            }

            operationResult =(operation, c);

            return operationResult;

        }

    }

public class CalMachine

    {

        private ICalculator calc;

        public CalMachine():this(new Calculator())

        {

        }

        public CalMachine(ICalculator obj)

        {

            this.calc = obj;

        }

       public (string operation, int result) Operate(string operationType, int a , int b)

        {

            return calc.DoOperation(operationType, a, b);

        }

    }

Now create a unit test case project and add the reference of library project to the unit test case project
Then install the Moq using nuget package manager. Mock the interface and pass that object to the instance. Then setup the method DoOperation, where the method mock and returns the response which has mentioned in the Returns

[TestClass]

    public class UnitTest1

    {

        [TestMethod]

        public void TestMethod1()

        {

            // Arrange

            Moq.Mock<ICalculator> cal = new Moq.Mock<ICalculator>();

         cal.Setup(x => x.DoOperation(It.IsAny<string>(), It.IsAny<int>(), It.IsAny<int>()))                                        .Returns(("add", 3));

            CalMachine machine = new CalMachine(cal.Object);

            // ACT

            (string operation, int result) result = machine.Operate("add", 1, 3);

            // Assert

            Assert.AreEqual("add", result.operation);

            Assert.AreEqual(3, result.result);

        }

    }

From this code you can learn how to write a unit test case for c# project using Moq. 

Mock HttpClient Using HttpMessageHandler in Moq

In this Post we are going to see how to mock the HttpClient using HttpMessageHandler in Moq. For this first we will create sample console app, which retrieves the data from RestApi call.

namespace TestCaseApp

{

    public class Post

    {

        public int userId { set; get; }

        public int id { set; get; }

        public string title { set; get; }

        public string body { set; get; }

    }

}

Above class is a model class

namespace TestCaseApp

{

    public interface IPostUtility

    {

       Task<Post> GetData();

    }

}

From the below method you may see that we are consuming a rest api using Httpclient

namespace TestCaseApp

{

    public class PostUtility: IPostUtility

    {

        HttpClient _client;

        public PostUtility()

        {

        }

        public PostUtility(HttpClient client)

        {

            _client = client;

        }

        public async Task<Post> GetData()

        {

            using (var client = _client ?? new HttpClient())

            {

                HttpResponseMessage response = await client.GetAsync("https://jsonplaceholder.typicode.com/posts/1");

                response.EnsureSuccessStatusCode();

                using (HttpContent content = response.Content)

                {

                    string responseBody = await response.Content.ReadAsStringAsync();                   

                    var articles = JsonConvert.DeserializeObject<Post>(responseBody);

                    return articles;

                }

            }

        }

    }

}

Main.cs

************

class Program

    {

        static void Main(string[] args)

        {

            IPostUtility post = new PostUtility();

            var _post =  post.GetData();

            _post.Wait();

            var result = _post.Result;

            Console.WriteLine($" Id: {result.id}, body: {result.body}");

            Console.ReadLine();

        }      

    }

output:

***********

Id: 1, body: quia et suscipit

Above main method is the calling part , where we can see the result of Post Data. Now are going to write a moq for this method and mock the HttpClient

To Mock the HttpClient we need to use HttpMessageHandler class, mock this class and pass this is in constructor of HttpClient.

Test Method:

***************

using System;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using TestCaseApp;

using System.Net.Http;

using Moq;

using Moq.Protected;

using System.Threading.Tasks;

using System.Threading;

namespace TestCaseAppTests

{

    [TestClass]

    public class PostUtilityTests

    {

        private IPostUtility _postUtility;

        private Mock<HttpMessageHandler> _mockHttpMessageHandler;

        [TestInitialize]

        public void Initialize()

        {

            _mockHttpMessageHandler = new Mock<HttpMessageHandler>();

            _postUtility = new PostUtility(new HttpClient(_mockHttpMessageHandler.Object));

        }

        [TestMethod]

        public void GetPostData()

        {

            // Arrange          

            _mockHttpMessageHandler.Protected().Setup<Task<HttpResponseMessage>>("SendAsync",

                ItExpr.IsAny<HttpRequestMessage>(),

                ItExpr.IsAny<CancellationToken>())

                .Returns(Task.FromResult(new HttpResponseMessage() {

                    StatusCode = System.Net.HttpStatusCode.OK,Content =new StringContent(PostString())

                }));

            // Act

            var _result = _postUtility.GetData();

            _result.Wait();

            var data = _result.Result;

            // Assert

            Assert.AreEqual(data.body, "sample");

           

        }

        private string PostString()

        {

            return "{\"userId\": 1,\"id\": 1,\"title\": \"rajTitle\",\n  \"body\": \"sample\"}";

        }

    }

}

From this post you can learn how to mock the HttpClient using the  HttpMessageHandler in Moq