vs.2008中如何对抽象类私有方法进行单元测试

OleDbReader是个抽象类，用于封装通过OledDB基本方法，而ExcelOleDB是他的一个实现。而我测试一下抽象类中
的私有方法GetData。开示的代码如下：

PrivateObject param0 =new PrivateObject(new ExcelOledDBReader());
OleDbReader_Accessor target = new OleDbReader_Accessor(param0);
//some code...
DataTable actual = target.GetData(filePath, top, columnInfos, skipLength);
Assert.AreEqual(10, actual.Rows.Count);

但是发觉会报
Test method FileSepc.Test.OleDbReaderTest.GetDataTest threw exception: System.ArgumentException:
The member specified (GetData) could not be found. You might need to regenerate your private accessor,
or the member may be private and defined on a base class. If the latter is true, you need to pass the type
that defines the member into PrivateObject's constructor.

后来为praram0变量加上PrivateType类的实例后就可以啦。 代码如下：
PrivateType type=new PrivateType(typeof(OleDbReader));
PrivateObject param0 =new PrivateObject(new ExcelOledDBReader(),type);
OleDbReader_Accessor target = new OleDbReader_Accessor(param0);
//some code...
DataTable actual = target.GetData(filePath, top, columnInfos, skipLength);
Assert.AreEqual(10, actual.Rows.Count);

from:http://blog.csdn.net/luqizheng/article/details/2959768