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Xunit new in memory database DBContext Class has live data

I am trying to unit test with the EF Core in-memory database like so:
namespace ContosoTests
{
public class TrendServiceTests
{
private static Microsoft.EntityFrameworkCore.DbContextOptions<TestContext> options = new
Microsoft.EntityFrameworkCore.DbContextOptionsBuilder<TestContext>()
.UseInMemoryDatabase(Guid.NewGuid().ToString())
.Options;
private static TestContext _context = new TestContext(options);
private readonly TrendService trendService = new TrendService(_context);
private void SeedInMemoryDb()
{
if (!_context.TrendHistories.Any())
{
_context.TrendHistories.Add(new TrendHistory { IsActive = true, Quarter = E_Quarter.Q1,
TrendYear = 2020 });
}
if (!_context.Controls.Any())
{
_context.Controls.Add(new Control { IsActive = true});
_context.Controls.Add(new Control { IsActive = true});
_context.Controls.Add(new Control { IsActive = false});
}
_context.SaveChanges();
}
}
My TestContext inherits from my live context class to avoid the error:
Services for database providers 'Microsoft.EntityFrameworkCore.InMemory', 'Microsoft.EntityFrameworkCore.SqlServer' have been registered in the service provider. Only a single database provider can be registered in a service provider
So my TestContext just looks like:
public class TestContext : ContosoContext
{
public TestContext(DbContextOptions<TestContext> options)
{
}
public TestContext()
{
}
}
When I use the new instance of TestContext (_context) in my test class, all the live data for ContosoContext is there.
I was expecting it to be a new instance of the context class with no data so that I could test my DAL code with controlled data. But this is not the case.
I am fairly new to unit testing so any help is much appreciated.
Edit:
Here are the relevant parts of my contoso context class
public class ContosoContext: IdentityDbContext<ContosoApplicationUser>
{
public ContosoContext(DbContextOptions<ContosoContext> options) : base
(options)
{
}
public ContosoContext()
{
}
//all my DBSets here
protected override void OnConfiguring(DbContextOptionsBuilder
optionsBuilder)
{
optionsBuilder.UseSqlServer("MyConnectionString");
}
}
So the issue is that my onconfiguring method handles the connection string directly??

To fix the error you need to remove optionsBuilder.UseSqlServer("MyConnectionString"); in OnConfiguring method to avoid registering multiple database providers, change it to this:
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if(!optionsBuilder.IsConfigured)
optionsBuilder.UseSqlServer("MyConnectionString");
}

Is there a way to Mock a View in EF Core?

I'm using EF Core "In Memory" database but having trouble mocking a view.
var options = new DbContextOptionsBuilder<MyContext>()
.UseInMemoryDatabase(databaseName: "TestDatabase")
.Options;
// Insert seed data into the database using one instance of the context
using (var context = new MyContext(options))
{
// insert test values into entities here (omitted)...
// I want some test values for a View
context.MyView.AddRange( viewEntity1, viewEntity, ... etc );
context.SaveChanges();
}
At runtime, when attempting to add the view entities, the following exception is raised:
System.InvalidOperationException: Unable to track an instance of type
'MyView' because it does not have a primary key. Only entity types
with primary keys may be tracked.
The reason I want to mock the View is that I want to test some LINQ queries that join to the View.
Any ideas?
// Entity
public class MyView
{
public string UserId {get;set;}
public int CentreId {get;set;}
}
// Context
...
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
...
modelBuilder.Entity<MyView>()
.HasNoKey()
.ToView("MyView");
}

No, the in-memory provider doesn't support views. It's a relational operation, same as the FromSql* and ExecuteSql* methods.
AddRange won't work on a view regardless of the provider.
You can test views; there are a couple of options:
Do integration tests with a real database
Use a better provider, possibly SQLite
Use a testing package that allows you to mock the view
I maintain one of said testing packages, EntityFrameworkCore.Testing, which does allow you to easily unit test SUTs that depend on views.

You should not mock anything at the Entity Framework level. Don't mock what you don't own.
In general, you should not be mocking implementation detail, which is what a view is - The consumer of your code should not need to know that it's interacting with a view, but that it's interacting with some data source. Otherwise your tests will end up breaking when you change the implementation detail, which is not what should be happening.
If you want to test how your controllers (or similar) interact with Entity Framework, you should use the Repository pattern and mock the Repository instead. If that's the case, you should not be mocking anything and instead should use a real database to test against.
If you want to test how your repositories interact with the database, you can use an integration test to test this. Repositories should be simple with very little business logic, so there is not much reason to unit test them to begin with.

Yes, you sure can....
Here is what I am using for my setup
Moq (for...mocks)
Lamar (for Dependency Injection)
STANDARD EF CORE VIEW:
Here the code for one of my view-definitions.
// EntityConfiguration
internal class ProjectStatusDetailConfiguration : IEntityTypeConfiguration<ProjectStatusDetail>
{
public void Configure(EntityTypeBuilder<ProjectStatusDetail> builder)
{
// SQL View
builder.ToView("vProjectStatus", "dbo")
.HasKey(e => e.ProjectId);
}
}
// Concrete DbContext
public class ProjectDbContext : DbContext
{
private IConfigurationRoot _settings;
public ProjectDbContext()
{
// NOTE: You must have this constructor for Migrations to work
BuildAppConfiguration();
}
public ProjectDbContext(DbContextOptions<ProjectDbContext> options) : base(options)
{
// NOTE: This constructor is used at the IServiceProvider layer
BuildAppConfiguration();
}
public virtual DbSet<Project> Project { get; set; }
public virtual DbSet<ProjectStatusDetail> vProjectStatusDetail { get; set; }
private void BuildAppConfiguration()
{
var builder = new ConfigurationBuilder();
builder.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json");
_settings = builder.Build();
}
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
// Default Configuration (if none is provided by the app)
if (!optionsBuilder.IsConfigured)
optionsBuilder.UseSqlServer(_settings.GetConnectionString(JsonSettings.ConnectionStrings.DefaultDb));
}
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
// GLOBAL Configurations
builder.ApplyGlobalEntityConfiguration(new AuditableStandardUserNameGlobalConfiguration());
// ENTITY Configurations
builder.ApplyConfiguration(new ProjectConfiguration());
// SQL VIEW Configurations
builder.ApplyConfiguration(new ProjectStatusDetailConfiguration());
}
}
// Lamar ServiceRegistry (for the business-layer)
public class ContainerRegistry : ServiceRegistry
{
public ContainerRegistry()
{
Scan(scan =>
{
scan.TheCallingAssembly();
scan.WithDefaultConventions();
scan.LookForRegistries();
scan.SingleImplementationsOfInterface();
});
// --------
// DATABASE
For<DbContext>().Use<ProjectDbContext>();
For(typeof(IAuditableRepository<>)).Use(typeof(GenericAuditableRepository<>));
ForConcreteType<ProjectUnitOfWork>().Configure.Setter<DbContext>().Is<ProjectDbContext>();
// Policies
Policies.Add<GenericAuditableRepositoryConfiguredInstancePolicy>(); //<-- Sets CTOR at Runtime
Policies.Add<UnitOfWorkConfiguredInstancePolicy>(); //<-- Sets CTOR at Runtime
}
}
// SINGLE POINT OF ENTRY: Consumes & "serves-up" your App's Registry
public static class IoC
{
public static ServiceRegistry Build()
{
var registry = new ServiceRegistry();
// Registration
registry.IncludeRegistry<ContainerRegistry>();
return new ServiceRegistry(registry);
}
}
UNIT TESTING SETUP:
Here the code for my unit testing setup. Obviously, I am still working-on the DbSetProxy's query...but here it is anyway.
// Lamar ServiceRegistry (for the unit test)
internal class ContainerRegistry : ServiceRegistry
{
public ContainerRegistry()
{
// This is where you will SHIM all your Stubs/Fakes
For<IWindowsIdentityHelper>().Use<UnitTests.WindowsIdentityHelperStub>(); //<-- Stub
}
}
// SINGLE POINT OF ENTRY: Consume all Registry's (for the unit testing-layer)
public static class IoC
{
public static ServiceRegistry Build()
{
var registry = new ServiceRegistry();
// Notice you can bring-in many ServiceRegistry's
// Just be sure to apply your "stubbing" registry last
registry.IncludeRegistry<Bushido.WorkflowComponent.DependencyResolution.ContainerRegistry>();
registry.IncludeRegistry<Bushido.Project.Business.DependencyResolution.ContainerRegistry>();
registry.IncludeRegistry<Bushido.WorkflowComponent.UnitTests.DependencyResolution.ContainerRegistry>();
return new ServiceRegistry(registry);
}
}
// This base class class does the heavy-lifting
public class UnitTestBase
{
protected IContainer Container { get; private set; }
protected Builder Builder { get; set; } = new Builder();
[TestInitialize()]
public virtual void Initialize()
{
IHostBuilder hostBuilder = CreateHostBuilder(null);
IHost host = hostBuilder.Build();
IServiceScope serviceScope = host.Services.CreateScope();
IServiceProvider serviceProvider = serviceScope.ServiceProvider;
Container = serviceProvider.GetRequiredService<IContainer>();
}
[TestCleanup()]
public virtual void Cleanup()
{
Container.Dispose();
Container = null;
}
private IHostBuilder CreateHostBuilder(string[] args)
{
var builder = new HostBuilder()
.ConfigureAppConfiguration((hostingContext, config) =>
{
config.AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);
})
// You must apply the Lamar Factory
.UseServiceProviderFactory<ServiceRegistry>(new LamarServiceProviderFactory())
.ConfigureServices((hostContext, services) =>
{
var databaseName = Guid.NewGuid().ToString();
// Add Lamar & Apply Scoping here (not in your ServiceRegistry's)
services.AddLamar(IoC.Build());
services.AddScoped<ProjectUnitOfWork>();
services.AddScoped<WorkflowComponentUnitOfWork>();
services.AddScoped<ProjectDbContext>();
services.AddScoped<WorkflowComponentDbContext>();
services.AddDbContext<ProjectDbContext>((provider, options) => options.UseInMemoryDatabase(databaseName), ServiceLifetime.Singleton);
services.AddDbContext<WorkflowComponentDbContext>((provider, options) => options.UseInMemoryDatabase(databaseName), ServiceLifetime.Singleton);
});
return builder;
}
}
// This base class contains the common setup for your VIEWS DbSetProxy
public class DataScenarioBase
{
protected static DbSet<TEntity> CreateDbSet<TEntity>(IQueryable<TEntity> collection) where TEntity : class
{
var stubDbSet = new Mock<DbSet<TEntity>>();
stubDbSet.As<IQueryable<TEntity>>().Setup(m => m.Provider).Returns(collection.Provider);
stubDbSet.As<IQueryable<TEntity>>().Setup(m => m.Expression).Returns(collection.Expression);
stubDbSet.As<IQueryable<TEntity>>().Setup(m => m.ElementType).Returns(collection.ElementType);
stubDbSet.As<IQueryable<TEntity>>().Setup(m => m.GetEnumerator()).Returns(collection.GetEnumerator());
return stubDbSet.Object;
}
}
// This is a sample DataScenario
public class ProjectDefaultDataScenario : DataScenarioBase
{
public void Load(IContainer container)
{
var unitOfWork = container.GetInstance<ProjectUnitOfWork>();
// DATA
LoadDefaultData(unitOfWork) //<-- you can pre-load default data into the UnitOfWork here too
// VIEWS
var dbContext = ((ProjectDbContext)unitOfWork.DbContext);
dbContext.vProjectStatusDetail = CreateDbSet<ProjectStatusDetail>(ProjectStatusDetailQuery(unitOfWork));
// Inject
container.GetNestedContainer().Inject(unitOfWork); //<-- This (along with scoping) ensures the right instance is always passed back
}
private IQueryable<ProjectStatusDetail> ProjectStatusDetailQuery(ProjectUnitOfWork unitOfWork)
{
var query = (from project in unitOfWork.Project
select new ProjectStatusDetail
{
ProjectId = project.Id,
ProjectName = project.ProjectName,
ObjectStateName = "Testing 123",
ObjectStateDateTime = DateTime.Now,
});
return query;
}
}
// Here is a sample Unit Test
[TestMethod]
public void ProjectProvider_WorkflowProvider_ObjectState_New()
{
// -----
// ARRANGE
Builder.WorkflowDefaultSetup.Load(Container);
Builder.ProjectDefaultSetup.Load(Container);
var project = new Project();
project.ProjectName = "Red Barchetta";
project.Description = "To keep it as new has been our dearest dream";
// -----
// ACT
var provider = Container.GetRequiredService<ProjectProvider>();
provider.CreateProject(project);
// -----
// ASSERT
Assert.IsTrue(project.Id > 0);
Assert.IsNotNull(project.ObjectState);
Assert.IsInstanceOfType(project.ObjectState, typeof(Bushido.Project.Business.StateManagement.Project.New));
}

ASP.NET MVC Initializer doesn't seed Database during Update-Database

The tagged duplicate question uses a custom context, I'm using the default ApplicationDbContext.
I'm confused why data isn't seeded whenever I run Update-Database. I read the other questions with answers but unfortunately they're using a custom Context, I'm using the default ApplicationDbContext. They seem to have the same answers but they don't work on my end.
I have the following done;
I have a custom Initializer:
public class PostInitializer : DropCreateDatabaseAlways<ApplicationDbContext>
{
protected override void Seed(ApplicationDbContext db)
{
var posts = new List<Post>
{
new Post()
{
Content = "TestA"
},
new Post()
{
Content = "TestB"
}
};
posts.ForEach(p => db.Posts.Add(p));
db.SaveChanges();
}
}
In My Global Asax:
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
// call PostInitializer here
Database.SetInitializer(new PostInitializer());
AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
}
}
My Model:
public class Post
{
[Key]
public int PostId { get; set; }
public string Title { get; set; }
public string Content { get; set; }
public DateTime? DateTimeCreated { get; set; }
}
I've tried deleting the DB and running Update-Database after, however data still isn't seeded.

Write your PostInitializer as follows:
public static class PostInitializer
{
public static void Seed()
{
using (ApplicationDbContext dbContext = new ApplicationDbContext())
{
if (dbContext.Database.Exists())
{
if(!dbContext.Posts.Any())
{
var posts = new List<Post>
{
new Post()
{
Content = "TestA"
},
new Post()
{
Content = "TestB"
}
};
posts.ForEach(p => dbContext.Posts.Add(p));
dbContext.SaveChanges();
}
}
}
}
}
Then register it as follows:
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
PostInitializer.Seed(); // <-- Here it is
AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
}
}

Ok my bad. What solved this was running the application. I thought the seeding would happen during Update-Database. This is what worked for me;
Run App
Access Controller with the Model concerned in Initializer, accessing at least the Index page worked for me (localhost/posts)
During Access, the Database will be dropped and created, then seeded with whatever specified in the Initializer
Close any SQL tabs on Visual Studio that is connected to the target DB as it might throw an error during Drop Database

C# EF Code first - init database (create table) and enable migrations

I'm updating a webform app to a mvc app but I have an issue.
I would like to create automatically the AspNetUsers tables when I try, for the first time,to log in through the webApp
Below the error messages:
The target context 'PROJECT.Data.DataContext' is not constructible.
Add a default constructor or provide an implementation of
IDbContextFactory.
Model compatibility cannot be checked because the database does not contain model metadata. Model compatibility can only be checked for
databases created using Code First or Code First Migrations.
The first one is fired with the code below:
Database.SetInitializer(new MigrateDatabaseToLatestVersion<DataContext, MyConfiguration>());
public class MyConfiguration : DbMigrationsConfiguration<DataContext>
{
public MyConfiguration()
{
this.AutomaticMigrationsEnabled = true;
}
protected override void Seed(DataContext context)
{
InitializeIdentityForEF(context);
base.Seed(context);
}
public void InitializeIdentityForEF(DataContext db)
{
// create admin user with role and claims
}
}
The second one:
Database.SetInitializer(new ApplicationDbInitializer());
public class ApplicationDbInitializer : DropCreateDatabaseIfModelChanges<DataContext>
{
protected override void Seed(DataContext context)
{
InitializeIdentityForEF(context);
base.Seed(context);
}
public void InitializeIdentityForEF(DataContext db)
{
// create admin user with role and claims
}
}
I think that I can fix this issue if I enable the the migration through the console but I would like to implement everything in the code. Any idea to mix theses two code above?
NOTE: I just want to create the AspNetUser table because I'm using "Database First" once they are created.
public class DataContext : DbContext, IEntitiesContext
{
private static readonly object Lock = new object();
private static bool _databaseInitialized;
public DataContext(string nameOrConnectionString, ILogger logger) : base(nameOrConnectionString)
{
Database.Log = logger.Log;
if (_databaseInitialized)
{
return;
}
lock (Lock)
{
if (!_databaseInitialized)
{
Database.SetInitializer(new MigrateDatabaseToLatestVersion<DataContext, MyConfiguration>());
Database.SetInitializer(new ApplicationDbInitializer());
_databaseInitialized = true;
}
}
}

Automapper, Mapping config isn't persisting

So the problem.
Ive added
AutoMapperConfig.Configure();
to the application_Start in global.asax
it runs the code
Mapper.Initialize(x =>
{
x.AddProfile<DomainToViewModelMappingProfile>();
x.AddProfile<ViewModelToDomainMappingProfile>();
});
Mapper.AssertConfigurationIsValid();
which runs
public class DomainToViewModelMappingProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<DBO.User, ViewModels.UserViewModel>();
}
}
and
public class ViewModelToDomainMappingProfile : Profile
{
protected override void Configure()
{
Mapper.Initialize(cfg =>
{
cfg.CreateMap<ViewModels.UserViewModel, DBO.User>();
});
}
}
and everything compiles and runs fine.
but in the controller:
UserViewModel model = new UserViewModel();
User user = userService.GetUser(2);
model = Mapper.Map<User, UserViewModel>(user); //this line fails as mapping doesnt exist
return View();
but if i add the mapping config in the controller method
Mapper.CreateMap<ViewModels.UserViewModel,DBO.User>();
UserViewModel model = new UserViewModel();
User user = userService.GetUser(2);
model = Mapper.Map<User, UserViewModel>(user); //Works great
return View();
it works fine.
ignore the different syntax with automapper. Ive tried the deprecated and new way of mapping and both fail.
Thanks

The problem is that you're calling Initialize method inside your Profile which leads to overriding your already existed mappings:
public class ViewModelToDomainMappingProfile : Profile
{
protected override void Configure()
{
// you should not to call Initialize method inside your profiles.
Mapper.Initialize(cfg =>
{
cfg.CreateMap<ViewModels.UserViewModel, DBO.User>();
});
}
}
And here, you have two ways:
Way #1 (using the static API - deprecated)
public class DomainToViewModelMappingProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<DBO.User, ViewModels.UserViewModel>();
}
}
public class ViewModelToDomainMappingProfile : Profile
{
protected override void Configure()
{
Mapper.CreateMap<ViewModels.UserViewModel, DBO.User>();
}
}
// initialize your mapper by provided profiles
Mapper.Initialize(x =>
{
x.AddProfile<DomainToViewModelMappingProfile>();
x.AddProfile<ViewModelToDomainMappingProfile>();
});
Mapper.AssertConfigurationIsValid();
Way #2 (using the instance API)
// in this case just call CreateMap from Profile class - its the same as CreateMap on `cfg`
public class DomainToViewModelMappingProfile : Profile
{
public DomainToViewModelMappingProfile()
{
CreateMap<DBO.User, ViewModels.UserViewModel>();
}
}
public class ViewModelToDomainMappingProfile : Profile
{
public ViewModelToDomainMappingProfile()
{
CreateMap<ViewModels.UserViewModel, DBO.User>();
}
}
// initialize you mapper config
var config = new MapperConfiguration(cfg => {
cfg.AddProfile<DomainToViewModelMappingProfile>();
cfg.AddProfile<ViewModelToDomainMappingProfile>();
});
// and then use it
var mapper = config.CreateMapper();
// or
var mapper = new Mapper(config);
var dest = mapper.Map<Source, Dest>(new Source());
In the Way #2 you will need to store you mapper configuration somewhere (static field, DI), and then use it inside your controller. I would like to suggest to inject the Mapper instance into your controller (e.g. using some DI container).
Hope it will help.

try to override "ProfileName" :
public class DomainToViewModelMappingProfile : Profile
{
public override string ProfileName
{
get
{
return "DomainToViewModelMappingProfile";
}
}
protected override void Configure()
{
Mapper.CreateMap<DBO.User, ViewModels.UserViewModel>();
}
}

OK, thanks to MaKCbIMKo for pointing me in the right direction
As described i dont have to initialize as its already being done in the automapperconfig.
the syntax once in the profile is simply.
CreateMap<ViewModels.UserViewModel, DBO.User>();