Can I use dependancy injection with this lib?

[Pseudooo]

I'm trying to implement a test harness in order to run integration tests on my application. I can't seem to find much about injecting the mocked context in place of the standard context and when I do attempt to do this with:

IServiceProvider serviceProvider = new ServiceCollection()
                                        .AddEntityFrameworkInMemoryDatabase()
                                        .BuildServiceProvider();

var loggerMock = Mock.Of<ILogger<DataContext>>();
var contextOptions = new DbContextOptionsBuilder<DataContext>().UseInMemoryDatabase("xx")
                                                                .UseInternalServiceProvider(serviceProvider)
                                                                .Options;
var contextMock = Create.MockedDbContextFor<DataContext>(loggerMock, contextOptions);

services.AddDbContext<DataContext>(options =>
{
    options.UseInMemoryDatabase("xx");
    options.UseInternalServiceProvider(serviceProvider);
    options.ConfigureWarnings(
        warningsConfigurationBuilder
            => warningsConfigurationBuilder.Ignore(InMemoryEventId.TransactionIgnoredWarning));
},
    ServiceLifetime.Singleton);

I just get the following error:

Message: Unable to create instance of class ****.ClientLibrary.Test.ClientLibraryTest. Error: System.MissingMethodException: Constructor on type '****.Repository.DataContext' not found..

[Pseudooo]

Forgot to include version, am currently utilising v1.2.1

[rgvlee]

To answer the question directly, yes you could use the mocked db context with the MS DI container. But first, what is the use case/specific reason for using a service provider/DI container in your tests?

Typically you wouldn't use a service provider/DI container in a unit test. You want to test a single concern and to achieve this you generally end up mocking your dependencies; a service provider/DI container is a bit of a third wheel in that relationship. If you were doing integration tests you normally wouldn't mock your dependencies, db context included.

The following is a contrived example of what I'd consider contemporary usage in a unit test:

public interface IFoo
{
  void DidSomething();
}

public class Bar
{
    ILogger<Bar> _logger;
    DataContext _dbContext;
    IFoo _foo;

    public Bar(ILogger<Bar> logger, DataContext dbContext, IFoo foo)
    {
      _logger = logger;
      _dbContext = dbContext;
      _foo = foo;
    }

    public void DoSomething()
    {
      _foo.DidSomething();

      //other operations...
    }
}

I'd expect the unit test to something like

var mockedDbContext = Create.MockedDbContextFor<DataContext>(
    Mock.Of<ILogger<DataContext>>(), 
    new DbContextOptionsBuilder<DataContext>().UseInMemoryDatabase(Guid.NewGuid().ToString()).Options
);
var mockedFoo = Mock.Of<IFoo>();

var service = new Bar(Mock.Of<ILogger<Bar>>(), mockedDbContext, mockedFoo);

service.DoSomething();

Mock.Get(mockedFoo).Verify(x => x.DidSomething(), Times.Once);

//other more useful asserts...

If there is a genuine reason for using a service provider then you simply need to add the mocked db context like any other service:

var mockedDbContext = Create.MockedDbContextFor<DataContext>(
    Mock.Of<ILogger<DataContext>>(),
    new DbContextOptionsBuilder<DataContext>().UseInMemoryDatabase(Guid.NewGuid().ToString()).Options
);

services.AddSingleton<DataContext>(mockedDbContext);

[rgvlee]

Issue closed for now; happy to continue if further assistance is required.