Act Arrange 2

 using FakeXrmEasy;

using FakeItEasy;

using Microsoft.Xrm.Sdk;

using Xunit;

public class CaspPluginTests

{

    [Fact]

    public void Should_Call_CaspService_And_Set_Attribute()

    {

        // Arrange

        var context = new XrmFakedContext();

        var fakeService = A.Fake<ICaspService>();

        // Fake the method return value

        A.CallTo(() => fakeService.GetCaspMedicalData("123", "DLN456"))

            .Returns("{\"status\":\"success\"}");

        // Register your plugin and pass in the fake dependency

        var pluginContext = context.GetDefaultPluginContext();

        // Example: simulate a target entity

        var target = new Entity("contact") { Id = Guid.NewGuid() };

        target["pfx_contactid"] = "123";

        target["pfx_dln"] = "DLN456";

        pluginContext.InputParameters["Target"] = target;

        // Inject the fake dependency using constructor injection or a service locator

        var plugin = new CaspPlugin(fakeService); // You must design your plugin to accept it

        // Act

        context.ExecutePluginWith(plugin, pluginContext);

        // Assert — e.g. verify attribute set based on the fake result

        var updated = context.Data[target.LogicalName][target.Id];

        Assert.True(updated.Contains("pfx_result"));

        Assert.Equal("{\"status\":\"success\"}", updated["pfx_result"]);

    }

}

Act Arrnage

using Xunit;

using FakeItEasy;

using System.Net;

using System.Net.Http;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

using Microsoft.Xrm.Sdk;

public class CaspServiceTests

{

    private readonly IDataAccessEnvironmentVariables _envVarMock;

    private readonly ISystemConfigurationService _configServiceMock;

    private readonly ITraceLogger _loggerMock;

    private readonly IHttpClientFactoryWrapper _httpFactoryMock;

    private readonly CaspService _service;

    public CaspServiceTests()

    {

        _envVarMock = A.Fake<IDataAccessEnvironmentVariables>();

        _configServiceMock = A.Fake<ISystemConfigurationService>();

        _loggerMock = A.Fake<ITraceLogger>();

        _httpFactoryMock = A.Fake<IHttpClientFactoryWrapper>();

        _service = new CaspService(

            _envVarMock,

            _configServiceMock,

            _loggerMock,

            _httpFactoryMock

        );

    }

    private HttpClient CreateFakeHttpClient(HttpResponseMessage responseMessage)

    {

        var fakeHandler = A.Fake<HttpMessageHandler>();

        A.CallTo(() => fakeHandler.Send(

            A<HttpRequestMessage>._,

            A<CancellationToken>._))

            .Returns(responseMessage);

        return new HttpClient(fakeHandler);

    }

    [Fact]

    public void GetCaspMedicalData_ShouldThrow_WhenUrlIsMissing()

    {

        // Arrange

        A.CallTo(() => _envVarMock

            .GetEnvironmentVariableValueByDefinitionSchemaName(A<string>._))

            .Returns(null);

        // Act & Assert

        Assert.Throws<InvalidPluginExecutionException>(() =>

            _service.GetCaspMedicalData("123", "DLN456"));

    }

    [Fact]

    public void GetCaspMedicalData_ShouldReturnResponse_WhenSuccessful()

    {

        // Arrange

        var expectedJson = "{\"status\":\"success\"}";

        var fakeHttpResponse = new HttpResponseMessage(HttpStatusCode.OK)

        {

            Content = new StringContent(expectedJson, Encoding.UTF8, "application/json")

        };

        A.CallTo(() => _envVarMock

            .GetEnvironmentVariableValueByDefinitionSchemaName(A<string>._))

            .Returns(new Entity { ["value"] = "https://fake.url.com" });

        A.CallTo(() => _configServiceMock.RetrievePFXSystemConfigRecord())

            .Returns(new Entity("pfx_config"));

        A.CallTo(() => _httpFactoryMock.CreateClient(A<Entity>._))

            .Returns(CreateFakeHttpClient(fakeHttpResponse));

        // Act

        var result = _service.GetCaspMedicalData("123", "DLN456");

        // Assert

        Assert.Equal(expectedJson, result);

    }

    [Fact]

    public void GetCaspMedicalData_ShouldThrow_WhenHttpReturnsNotFound()

    {

        // Arrange

        var response = new HttpResponseMessage(HttpStatusCode.NotFound);

        A.CallTo(() => _envVarMock

            .GetEnvironmentVariableValueByDefinitionSchemaName(A<string>._))

            .Returns(new Entity { ["value"] = "https://fake.url.com" });

        A.CallTo(() => _configServiceMock.RetrievePFXSystemConfigRecord())

            .Returns(new Entity("pfx_config"));

        A.CallTo(() => _httpFactoryMock.CreateClient(A<Entity>._))

            .Returns(CreateFakeHttpClient(response));

        // Act & Assert

        Assert.Throws<HttpRequestException>(() =>

            _service.GetCaspMedicalData("123", "DLN456"));

    }

    [Fact]

    public void GetCaspMedicalData_ShouldReturnEmpty_WhenInternalServerError()

    {

        // Arrange

        var response = new HttpResponseMessage(HttpStatusCode.InternalServerError);

        A.CallTo(() => _envVarMock

            .GetEnvironmentVariableValueByDefinitionSchemaName(A<string>._))

            .Returns(new Entity { ["value"] = "https://fake.url.com" });

        A.CallTo(() => _configServiceMock.RetrievePFXSystemConfigRecord())

            .Returns(new Entity("pfx_config"));

        A.CallTo(() => _httpFactoryMock.CreateClient(A<Entity>._))

            .Returns(CreateFakeHttpClient(response));

        // Act

        var result = _service.GetCaspMedicalData("123", "DLN456");

        // Assert

        Assert.Equal(string.Empty, result);

    }

    [Fact]

    public void GetCaspMedicalData_ShouldLogAndThrow_WhenUnhandledExceptionOccurs()

    {

        // Arrange

        A.CallTo(() => _envVarMock

            .GetEnvironmentVariableValueByDefinitionSchemaName(A<string>._))

            .Returns(new Entity { ["value"] = "https://fake.url.com" });

        A.CallTo(() => _configServiceMock.RetrievePFXSystemConfigRecord())

            .Returns(new Entity("pfx_config"));

        A.CallTo(() => _httpFactoryMock.CreateClient(A<Entity>._))

            .Throws(new Exception("Unexpected failure"));

        // Act & Assert

        Assert.Throws<Exception>(() =>

            _service.GetCaspMedicalData("123", "DLN456"));

        A.CallTo(() => _loggerMock

            .Error(A<string>._, A<string>._, A<Exception>._))

            .MustHaveHappenedOnceExactly();

    }

}