Entity Framework 4.1 “Code First” SetInitializer not being called again after Database.Delete

问题

Trying to do some unit testing with EF 4.1 code first. I have my live db (SQL Server) and my unit test DB( Sql CE). After fighting (and losing) with EF, Sql CE 4.0 and Transaction support I decided the simplest way to run my test was to:

1. Create Db
2. Run Test
3. Delete Db
4. Rinse and repeat

I have my [Setup] and [TearDown] functions:

[SetUp]
public void Init()
{
    System.Data.Entity.Database.SetInitializer(new MyTestContextInitializer());
    _dbContext = ContainerFactory.Container.GetInstance<IContext>();
    _testConnection = _dbContext.ConnectionString;
}

[TearDown]
public void Cleanup()
{
    _dbContext.Dispose();
    System.Data.Entity.Database.Delete(_testConnection);
}

Issue is that System.Data.Entity.Database.SetInitializer does not call MyTestContextInitializer after the first test.

Hence the 2nd test then fails with:

System.Data.EntityException : The underlying provider failed on Open.
----> System.Data.SqlServerCe.SqlCeException : The database file cannot be found. Check the path to the database

TIA for any pointers

回答1:

I got around this by calling 'InitializeDatabase' manually. Like so:

   [SetUp]
    public void Init()
    {

        var initializer = new MyTestContextInitializer();
        System.Data.Entity.Database.SetInitializer(initializer);

        _dbContext = ContainerFactory.Container.GetInstance<IContext>();
        initializer.InitializeDatabase((MyTestContext)_dbContext);

        _testConnection = _dbContext.ConnectionString;
    }

    [TearDown]
    public void Cleanup()
    {
        System.Data.Entity.Database.Delete(_testConnection);

        _dbContext.Dispose();
    }

I think it may be a bug with EF 4.1 RC.

回答2:

It's not a bug, the initializer set with

System.Data.Entity.Database.SetInitializer

is only called when the context is created for the first time in the AppDomain. Hence, since you're running all your tests in a single AppDomain, it's only called when the first test is ran.

回答3:

It took me almost a day to find out what caused my strange unittest behaviour: the database connection stayed open or the database was not created with a every new test. I searched everywhere for the root of the cause: MSTest (no Admin rights or where working copies of files somehow deleted?), SQL Server Express/CE (login failure?), Unity (objects not disposed?) or Entity Framework (no proper database initialization?). It turned out to be EF. Thanks a lot for the answer!

来源：https://stackoverflow.com/questions/5494158/entity-framework-4-1-code-first-setinitializer-not-being-called-again-after-da