使用 nSubstitute 时不调用抽象处理方法

Question

我有这个基础（摘要）class:

public abstract class StreamWriterBuilderService : IStreamWriterService
{
    private Stream fs;
    private StreamWriter stream;

    public void WriteLine(
        string stringToWrite )
    {
        if ( stream == null )
        {
            throw new InvalidOperationException( "Tried to call WriteLine on an uninitialised StreamWriterBuilderService" );
        }

        stream.WriteLine( stringToWrite );
        Flush();
    }

    public void Flush()
    {
        if ( stream == null )
        {
            throw new InvalidOperationException( "Tried to call Flush on an uninitialised StreamWriterBuilderService" );
        }

        stream.Flush();
    }

    public void Initialise(
        string filePath )
    {
        Contract.Requires<ArgumentNullException>( filePath != null );

        fs = File.Open( filePath, FileMode.Append, FileAccess.Write, FileShare.ReadWrite );
        stream = new StreamWriter( fs );
        WriteLine("Initialised");
        Initialised = true;
    }

    public bool Initialised { get; private set; }

    #region Dispose Implementation

    ~StreamWriterBuilderService()
    {
        Dispose( false );
        Debug.WriteLine( false, "This StreamWriterBuilderService object was not disposed of" );
    }

    private bool _isDisposed;

    public virtual void Dispose()
    {
        Dispose( true );
        GC.SuppressFinalize( this );
    }

    protected virtual void Dispose(
        bool disposing )
    {
        if ( _isDisposed )
            return;

        if ( disposing && Initialised )
        {
            stream.Dispose();
            fs.Dispose();
            stream = null;
            fs = null;
        }

        _isDisposed = true;
    }

    #endregion Dispose Implementation
}

我正在对它进行单元测试：

    protected readonly string TargetFilePath = Path.GetTempFileName();
    protected const string Header = "Initialised";

    protected override void SetContext()
    {
        SUT = Substitute.For<StreamWriterBuilderService>();
    }

和...

    private string fileContents;
    private const string TestString = @"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!£$%^&*()+~@?><|¬";

    protected override void Because()
    {
        base.Because();
        SUT.Initialise( TargetFilePath );
        SUT.WriteLine( TestString );
        SUT.Flush();
        SUT.Dispose();
        fileContents = File.ReadAllText( TargetFilePath );
    }

我遇到的麻烦是：

SUT.Dispose();

实际上并没有在我的抽象 class 中调用我的 Dispose 方法，因为它被声明为虚拟方法。如果我删除虚拟方法，那么代码就会播放出来。但是，我需要保留虚拟方法，因为我需要在我的解决方案中的其他地方重写...

Answer 1

当您 substitute 像这样 class 时，虚拟方法将被替换。你可能想要一个部分替代品只替换 Dispose(bool).

Documentation about partial substitutes

和the second Paragraph here：

For starters, NSubstitute can only work with virtual members of the class, so any non-virtual code in the class will actually execute!

也就是说，虚拟方法不会执行。

我会创建一个用于测试目的的派生类型，只是为了删除 abstract，然后用它进行测试。

Answer 2

你应该使用：

var SUT = Substitute.ForPartsOf<StreamWriterBuilderService>();

这让您 fine control 了解要替换的特定内容。 因此，默认情况下，您的 Dispose 方法不会被替换。

或者，我的建议（针对此特定场景）是构建您自己的 StreamWriterBuilderServiceForTesting class（继承自 StreamWriterBuilderService）。 由于不涉及 NSubstitute，您可以根据需要定义其行为。

使用 nSubstitute 时不调用抽象处理方法

Abstracted Dispose Method not called when using nSubstitute

c#

abstract-class

unit-testing

nsubstitute