unit-testing - Entity Framework 集成测试 DropCreateDatabaseAlways 在测试之间不清除数据库

Question

我正在编写一组集成测试(使用 MS Test 进行单元测试，用于测试 Entity Framework 4.2 是否将所有类正确保存到数据库中)。

当我一一运行所有测试时，它们都可以正常工作。当我在一组中运行它们时 - 其中一些失败，因为返回了错误数量的对象 - 似乎数据库在测试开始时被清理一次，而不是在每次测试之间 - 即使我可以看到一个新的上下文被创建，然后为每个测试处理

有任何想法吗？

public class EmptyDataInitializer : DropCreateDatabaseAlways<myContext>
{
    protected override void Seed(myContext db)
    {
        //Do Nothing Create Empty Database
        db.SaveChanges();
        base.Seed(db);
    }
}

单元/集成测试的精简版

[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");
   }

}

逐步完成测试，我可以看到调用了 SetupTest 和 TearDownTest 方法，但我似乎没有在测试之间清理数据库。

Answer 1

好的甚至更好的答案 - 添加一个 database.Initialize(force: true);
进入 TestInitialize 方法。

[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.");
}