1. Add a new Basic Unit Test class called InMemoryEmailUpdateTest.cs to your unit test project.
2. Add a reference to the following NuGet packages:
   • Microsoft.CrmSdk.CoreAssemblies
   • XrmUnitTest.2016
   • Moq
3. Ensure that you have a reference to the Packt.Xrm.Extensions project.

4. Add the following using statements:

using Packt.Xrm.Extensions.Plugin; 
using Moq; 
using Microsoft.Xrm.Sdk; 
using Packt.Xrm.Entities; 
using DLaB.Xrm.LocalCrm; 
using DLaB.Xrm.Test; 

5. Add the following private instance variables:

private const int NumberOfDaysDifference = 10; 
private IServiceProvider _serviceProvider; 
private Mock<ITracingService> _tracingMock; 
private IOrganizationService _organizationServiceFake; 
private Guid _email1Guid; 
private Guid _email2Guid; 
private Guid _email3Guid; 

6. Add the following private SetupMock method to set up your fakes and mocks:

private void SetupMock() 
{ 
    var serviceProviderMock = new Mock<IServiceProvider>(); 
    _tracingMock = new Mock<ITracingService>(); 

    _organizationServiceFake = new LocalCrmDatabaseOrganizationService(LocalCrmDatabaseInfo.Create<OrganisationServiceContext>()); 
    var accountGuid = _organizationServiceFake.Create(new Account() { Name = "Packt Test" }); 
    _email1Guid = _organizationServiceFake.Create(new Email() { Subject = "Mock 1", RegardingObjectId = new EntityReference(Account.EntityLogicalName, accountGuid) }); 
    _email2Guid = _organizationServiceFake.Create(new Email() { Subject = "Mock 2", RegardingObjectId = new EntityReference(Account.EntityLogicalName, accountGuid) }); 
    _email3Guid = _organizationServiceFake.Create(new Email() { Subject = string.Empty, RegardingObjectId = new EntityReference(Account.EntityLogicalName, accountGuid) }); 

    var pluginContextMock = new Mock<IPluginExecutionContext>(); 
    var parameterCollection = new ParameterCollection(); 
    parameterCollection.Add("Target", new Account() { Id = accountGuid }); 
    pluginContextMock.Setup(c => c.InputParameters).Returns(parameterCollection); 
    var organisationServicefactoryMock = new Mock<IOrganizationServiceFactory>(); 
    organisationServicefactoryMock.Setup(f => f.CreateOrganizationService(It.IsAny<Guid>())).Returns(_organizationServiceFake); 
    serviceProviderMock.Setup(sp => sp.GetService(typeof(ITracingService))).Returns(_tracingMock.Object); 
    serviceProviderMock.Setup(sp => sp.GetService(typeof(IPluginExecutionContext))).Returns(pluginContextMock.Object); 
    serviceProviderMock.Setup(sp => sp.GetService(typeof(IOrganizationServiceFactory))).Returns(organisationServicefactoryMock.Object); 

    _serviceProvider = serviceProviderMock.Object; 
} 

7. Create the following test method:

[TestMethod] 
[TestCategory("InMemory")] 
public void Fake() 
{ 
   //Arrange  
   SetupMock(); 

   var plugin = new UpdateActivity(); 
   //Act 
   plugin.Execute(_serviceProvider);  

   //Assert 
   Assert.AreEqual(EmailState.Open, 
   _organizationServiceFake.GetEntity(new Id<Email>
   (_email1Guid)).StateCode); 
   Assert.AreEqual(DateTime.Now.Date.AddDays
   (NumberOfDaysDifference), _organizationServiceFake.GetEntity
   (new Id<Email>(_email1Guid)).ScheduledStart,
   "Start date not updated correctly for emails with a subject"); 
   Assert.AreEqual(EmailState.Open,
   _organizationServiceFake.GetEntity(new Id<Email> 
   (_email2Guid)).StateCode); 
   Assert.AreEqual(DateTime.Now.Date.AddDays
   (NumberOfDaysDifference),
   _organizationServiceFake.GetEntity(new Id<Email>
   (_email2Guid)).ScheduledStart, "Start date not updated
   correctly for emails with a subject"); 
   Assert.AreEqual(EmailState.Canceled,
   _organizationServiceFake.GetEntity(new Id<Email>
   (_email3Guid)).StateCode,  "Email without a subject was not
   cancelled"); 
}

8. Run your unit test in debug mode.