模拟IDBEngine以使用Moq返回模拟的DbDataReader

Question

以下测试：

Mock<IDBEngine> dbEngineMock = new Mock<IDBEngine>();
Mock<DbDataReader> dbReader = new Mock<DbDataReader>();

dbEngineMock.Setup(x => x.Dispose());
dbEngineMock.Setup(x => x.ExecuteReader(It.IsAny<string>())).Returns(dbReader.Object);

dbReader.SetupSequence(x => x.Read()).Returns(true).Returns(false);
dbReader.Setup(x => x["Column_Name"]).Returns(importFlag);

SomeClass myInstance = new SomeClass();
Assert.NotNull(myInstance.DoStuff(dbEngineMock.Object))

每次dbEngineMock必须执行ExecuteReader()方法时，返回 null 。

private int? DoStuff(IDbEngine aDBEngine)
{
    using (DbDataReader reader = aDBEngine.ExecuteReader(select))
    {
       while (reader.Read()) //null reference exception
       {

我想念什么吗？

有关DbDataReader的更多信息：

public abstract class DbDataReader : MarshalByRefObject, IDataReader, IDisposable, IDataRecord, IEnumerable

和IDBEngine：

 public interface IDBEngine : IDisposable
    {
    DbDataReader ExecuteReader(string sqlCommand);