Entity Framework Integration tests DropCreateDatabaseAlways not clearing database between test - unit-testing

Question

I am writing a set of integration tests (Unit tests with MS Test which test that Entity Framework 4.2 is persisting all classes correctly to the database).
When I run all tests one by one they all work fine. When I run them in a group - some of them fail as the wrong number of objects are returned - it would seem that the db is being cleaned down once at the start of the tests and not in between each test - even though I can see a new context being created and then disposed of for each test
Any Ideas?
public class EmptyDataInitializer : DropCreateDatabaseAlways<myContext>
{
protected override void Seed(myContext db)
{
//Do Nothing Create Empty Database
db.SaveChanges();
base.Seed(db);
}
}
A Cut down version of the unit/integration Tests
[TestClass]
public class PersistanceTests
{
//Creating two instances of our Repository so that we can make sure that we are reading from our database rather than in-memory
private myContext _db;
private myContext _dbResults;
private readonly ISettings _configSettings;
public PersistanceTests()
{
_configSettings = MockRepository.GenerateStub<ISettings>();
_configSettings.ConnectionString = "data source=.;initial catalog=myContext_Test; Integrated Security=SSPI; Pooling=false";
Database.SetInitializer(new EmptyDataInitializer());
}
//This is called a single time after the last test has finished executing
[TestCleanup]
public void TearDownTest()
{
_db.Dispose();
_db = null;
_dbResults.Dispose();
_dbResults = null;
}
//This is called each time prior to a test being run
[TestInitialize]
public void SetupTest()
{
_db = new myContext(_configSettings);
_dbResults = new myContext(_configSettings);
// This forces the database to initialise at this point with the initialization data / Empty DB
var count = _db.Accounts.Count();
var resultCount = _dbResults.Accounts.Count();
if (count != resultCount) throw new InvalidOperationException("We do not have a consistant DB experiance.");
}
[TestMethod]
public void OrganisationPersistanceTest()
{
// Arrange
var apple = new Organisation { Name = "Apple" };
_db.Organisations.Add(apple);
// Act
_db.SaveChanges();
var organisationsCount = _dbResults.Organisations.Count();
var organisationsAppleCount = _dbResults.Organisations.Where(a => a.Id == apple.Id).Count();
var result = _dbResults.Organisations.FirstOrDefault(a => a.Id == apple.Id);
// Assert
Assert.IsTrue(organisationsCount == 1, string.Format("Organisations Count Mismatch - Actual={0}, Expected={1}", organisationsCount, 1));
Assert.IsTrue(organisationsAppleCount == 1, string.Format("Apple Organisations Count Mismatch - Actual={0}, Expected={1}", organisationsAppleCount, 1));
Assert.IsNotNull(result, "Organisations Result should not be null");
Assert.AreEqual(result.Name, apple.Name, "Name Mismatch");
}
//A Unit test
[TestMethod]
public void OrganisationWithNumberOfPeople_PersistanceTest()
{
// Arrange
var person = new Person { Firstname = "Bea" };
var anotherPerson = new Person { Firstname = "Tapiwa" };
var apple = new Organisation { Name = "Apple" };
apple.AddPerson(person);
apple.AddPerson(anotherPerson);
_db.Organisations.Add(apple);
// Act
_db.SaveChanges();
var organisationsCount = _dbResults.Organisations.Count();
var organisationsAppleCount = _dbResults.Organisations.Where(a => a.Id == apple.Id).Count();
var result = _dbResults.Organisations.FirstOrDefault(a => a.Id == apple.Id);
var peopleCountInOrganisation = result.People.Count();
// Assert
Assert.IsTrue(organisationsCount == 1, string.Format("Organisations Count Mismatch - Actual={0}, Expected={1}", organisationsCount, 1));
Assert.IsTrue(organisationsAppleCount == 1, string.Format("Apple Organisations Count Mismatch - Actual={0}, Expected={1}", organisationsAppleCount, 1));
Assert.IsNotNull(result, "Organisations Result should not be null");
Assert.AreEqual(result.People.Count, peopleCountInOrganisation, "People count mismatch in organisation Apple - Actual={0}, Expected={1}", peopleCountInOrganisation, 2);
Assert.AreEqual(result.Name, apple.Name, "Name Mismatch");
}
}
Stepping through the tests I can see the SetupTest and TearDownTest methods being called but I it does not seem to clean down the database between tests.

Answer 1

Okay even Better answer - add a database.Initialize(force: true);
into the TestInitialize method.
[TestInitialize]
public void SetupTest()
{
_db = new myContext(_configSettings);
_db.Database.Initialize(force: true);
_dbResults = new myContext(_configSettings);
// This forces the database to initialise at this point with the initialization data / Empty DB
var count = _db.Accounts.Count();
var resultCount = _dbResults.Accounts.Count();
if (count != resultCount) throw new InvalidOperationException("We do not have a consistant DB experiance.");
}

Answer 2

I use a helper for doing this kind of tasks:
public abstract class TestingHelper
{
public static void ClearDatabase()
{
DatabaseContext myDbContext = new DatabaseContext();
myDbContext.Database.Delete();
myDbContext.Database.Create();
//FillDatabase(lawyers); //<- OPTIONAL if you want to add rows to any type tables
}
}
And then use it in the SetUp of your test:
[SetUp]
public void MyTests_SetUp()
{
TestingHelper.ClearDatabase();
}