EF状态跟踪测试

[TestClass]
public class EFTest
{
    //测试EntityKey, EntityState, ObjectContext
    //1. Detach后EntityKey是否存在？  是
    //2. EntityKey占多大内存？    小
    //3. Entity所依附的ObjectContext被Dispose后，EntityState是否自动变为Detached? 否
    //4. 当MergeOption为NoTracking时，Entity中属性的改变是否会被跟踪？   不会，为Detached状态
    //4. Entity所依附的ObjectContext被Dispose后，Entity中属性的改变是否会被跟踪？
    [TestMethod]
    public void trackTest()
    {
        int id = 5;
        FinanceContext context = new FinanceContext();
        //DataContext在默认情况下的行为
        BusinessApplication entity = context.BusinessApplication.Where(b => b.Id == id).Single();
        Assert.AreEqual(EntityState.Unchanged, entity.EntityState);
        entity.Title = "改变一下";
        Assert.AreEqual(EntityState.Modified, entity.EntityState);
        context.Detach(entity);
        Assert.IsNotNull(entity.EntityKey);
        //在DataContext Dispose以后的行为
        entity = context.BusinessApplication.Where(b => b.Id == id).Single();
        context.Dispose();
        Assert.AreEqual(EntityState.Unchanged, entity.EntityState);
        entity.Title = "改变一下";
        Assert.AreEqual(EntityState.Modified, entity.EntityState);

        //DataContext当MergeOption.NoTracking时的行为
        context = new FinanceContext();
        entity = null;
        context.BusinessApplication.MergeOption = MergeOption.NoTracking;
        entity = context.BusinessApplication.Where(b => b.Id == id).Single();
        Assert.AreEqual(EntityState.Detached, entity.EntityState);
        entity.Title = "改变一下";
        Assert.AreEqual(EntityState.Detached, entity.EntityState);
        context.Dispose();

        //DataContext当MergeOption.OverwriteChanges时的行为
        context = new FinanceContext();
        entity = null;
        context.BusinessApplication.MergeOption = MergeOption.OverwriteChanges;
        entity = context.BusinessApplication.Where(b => b.Id == id).Single();
        Assert.AreEqual(EntityState.Unchanged, entity.EntityState);
        entity.Title = "改变一下";
        Assert.AreEqual(EntityState.Modified, entity.EntityState);
        context.Dispose();

    }
}

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