在基類中存根只讀屬性

Question

我有這樣的課：

public class Customer : CustomerBase
{
    // internals are visible to test
    internal string GenString()
    {
        // this actually composes a number of different properties 
        // from the parent, child and system properties
        return this.InfoProperty.Name + DateTime.Now.ToString() + "something else"; 
    }
}

// this class is in a 3rd party library, but from metadata it looks like this
public class CustomerBase
{
    public Info InfoProperty { get; }
}

我的測試看起來像這樣：

public class Tests
{
    public void MyTest()
    {
        using (ShimsContext.Create())
        {
            // Arrange
            /* I shim datetime etc. static calls */

            Fakes.StubCustomer c = new Fakes.StubCustomer()
            {
                InfoProperty = new Info("Name") // <- Error here because it's readonly
            };

            // Act
            string result = c.GenString();

            // Assert
            Assert.AreEqual(result, "whatnot");
        }
    }
}

所以我的問題是，如何對只讀屬性進行存根/填充，以便可以測試此功能？

Answer 1

將此吸氣劑包裝到可以被模擬覆蓋的臨時虛擬方法中怎么辦？

例如：

public class Customer : CustomerBase
{
  // internals are visible to test
  internal string GenString()
  {
    // this actually composes a number of different properties 
    // from the parent, child and system properties
    return InfoPropertyNameGetter() + DateTime.Now.ToString() + "something else"; 
  }

  public virtual string InfoPropertyNameGetter(){
    retrn this.InfoProperty.Name;
  }
}

Mock<Customer> mock = new Mock<Customer>();
mock.Setup(m => m.InfoPropertyNameGetter()).Returns("My custom value");

看起來有點像有效使用遺留代碼中 Introduce Instance Delegator模式。