NUnit FileAssert在MemoryStream和FileStream之间失败

Question

I have a test class that tests two that a generated xml file matches one that is already generated and known to be good. The test passes when comparing files written to disk. It fails when comparing the file still in memory to the known good file read from the disk, because the expected stream is 17 bytes longer.

testing class

[TestFixture]
class XmlExporterTest
{
    private const string ExpectedXMLFile = @"..\..\Projects\EXPECTED FILE.xml";

    private XmlExporter xmlExporter;

    [SetUp]
    public void SetUp()
    {
        // clean up from before, since we might want the info after the tests (if they fail for example)
        string[] filePaths = Directory.GetFiles(@"..\..\tmp");
        foreach (string f in filePaths)
        {
            File.Delete(f);
        }
    }

    // this always fails because the stream length is 17 bytes short
    [Test]
    public void TestExportToXMLStream()
    {
        // test write to stream
        using (Stream actualStream = xmlExporter.ExportToXML(true))
        {
            using (Stream expectedStream = new FileStream(ExpectedXMLFile, FileMode.OpenOrCreate, FileAccess.Read, FileShare.None))
            {
                FileAssert.AreEqual(expectedStream, actualStream);
            }
        }
    }

    // this always passes
    [Test]
    public void TestExportToXMLFile()
    {
        const string actualXMLFile = @"..\..\tmp\project1.xml";
        xmlExporter.ExportToXML(actualXMLFile, true);
        FileAssert.AreEqual(ExpectedXMLFile, actualXMLFile);
    }
}

XML exporting class

public class XmlExporter
{
    public void ExportToXML(string filename, bool normalizeZoom)
    {
        iexINSPECTIONXPERT arr = CreateSerializableObject(normalizeZoom);

        //serialize to an XML file
        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
        ns.Add("xxx", "http://www.example.com");
        using (TextWriter tr2 = new StreamWriter(filename))
        {
            XmlSerializer sr2 = new XmlSerializer(typeof(Foo));
            sr2.Serialize(tr2, arr, ns);
        }
    }

    /// <summary>
    /// Exports to XML only returning a MemoryStream object.
    /// Note that the stream must be disposed of by the caller.
    /// </summary>
    /// <param name="normalizeZoom"></param>
    /// <returns></returns>
    public MemoryStream ExportToXML(bool normalizeZoom)
    {
        iexINSPECTIONXPERT arr = CreateSerializableObject(normalizeZoom);

        //serialize to an XML file
        XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
        ns.Add("xxx", "http://www.example.com");
        var stream = new MemoryStream();
        XmlSerializer sr2 = new XmlSerializer(typeof(Foo));
        sr2.Serialize(stream, arr, ns);
        return stream;
    }
}

other class

[System.Xml.Serialization.XmlRootAttribute(Namespace = "http://www.example.com", ElementName = "Foo")]
public class Foo
{
    [XmlElementAttribute(Namespace = "", ElementName = "BAR")]
    public BAR fi;
}

Answer 1

You need to use the same encoding when writing to file and when writing to a memory stream, for example using Encoding.Default in both cases.

File:

using (TextWriter tr2 = new StreamWriter(filename, false, Encoding.Default))

Memory:

var memory = new MemoryStream();
var writer = new StreamWriter(memory, Encoding.Default);
sr2.Serialize(writer, arr, ns);