VSTO Unit Testing Office AddIn in C # .NET via RequestComAddInAutomationService

Question

I have worked and read various StackOverflow questions and other tutorials and documentation in recent weeks (some of which are given below) to try and find a way to unit test VSTO AddIn.

Unfortunately, this always leads to an exception E_NOINTERFACEin my tests.

The code I use is shown below - one extract of the partial ThisAddin class, overriding RequestComAddinAutomationService, another that describes the interface of the test utility, the test itself, as well as an additional collection confirming that the AddIn assembly and its internal elements are visible for the test.

My question is : why does this not work? I am sure that this follows generally accepted VSTO testing practice.

If this is not possible below, how do I go through VSTO testing? Is .NET remoting / IPC the only solution?

ThisAddin.cs

public partial class ThisAddin 
{
    #region Testing Utilities

    private AddinHelper _comAddinObject;

    protected override object RequestComAddInAutomationService()
    {
        // This is being called when I debug/run my project, but not when I run the tests
        return _comAddinObject ?? (_comAddinObject = new AddinHelper());
    }

    #endregion
}

#region Testing Utilities

[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface IAddinHelper
{
    Presentation GetPresentation();
    string GetString();
}

[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[ComSourceInterfaces(typeof(IAddinHelper))]
public class AddinHelper : StandardOleMarshalObject, IAddinHelper
{
    public Presentation GetPresentation()
    {
        return Globals.ThisAddin... [...];
    }

    public string GetString()
    {
        return "Hello World!";
    }
}

#endregion

AssemblyInfo.cs

[assembly: InternalsVisibleTo("MyProject.Tests")]

MyUnitTest.cs (has a link to MyProject)

[TestClass]
public class BasicTest
{
    [TestMethod]
    public void TestInstantiates()
    {
        var application = new Application();
        var doc = application.Presentations.Open(@"C:\Presentation.pptx",
            MsoTriState.msoFalse, MsoTriState.msoFalse, MsoTriState.msoFalse);
        var comAddins = application.COMAddIns;
        var comAddin = comAddins.Item("MyProject"); // Returns okay
        var comObject = (IAddinHelper) comAddin.Object; // Exception occurs

        Assert.AreEqual(true, true); // Never reached

        doc.Close();
    }
}

In addition, the project settings are set to "Registration for COM interoperability", and Visual Studio starts without errors - starting it as a non-administrator results in DLLs not being registered; therefore, I also know that COM objects are registered .

Resulting exception

"System.InvalidCastException" MyProject.Tests.dll, : COM- "System.__ ComObject" "MyProject.IAddinHelper". , QueryInterface COM- IID '{59977378-CC79-3B27-9093-82CD7A05CF74}' - : ( HRESULT: 0x80004002 (E_NOINTERFACE)).

StackOverflow

• VSTO #
• VSTO
• VSTO, COMAddIns RequestComAddInAutomationService (Register for COM Interop )
• COM- , #? ( STAThread)
• https://sqa.stackexchange.com/questions/2545/how-do-i-unit-test-word-addin-written-in-c

Microsoft

• https://blogs.msdn.microsoft.com/varsha/2010/08/17/writing-automated-test-cases-for-vsto-application/ < - , , , .
• https://msdn.microsoft.com/en-us/library/bb608621.aspx
• : https://msdn.microsoft.com/en-us/library/bb386298.aspx

, VSTO .

Answer 1

PIA Microsoft.Office.Interop.PowerPoint .Net reference.

Unit Test Microsoft Powerpoint 1X.0 COM - ActiveX.

, : Microsoft.Office.Interop.Powerpoint

---

, , :

'Microsoft.CSharp.RuntimeBinder.CSharpArgumentInfo.Create'

, .Net Microsoft.CSharp.dll Unit Test.

---

, .

GUID ( ):

[ComVisible(true)]
[Guid("B523844E-1A41-4118-A0F0-FDFA7BCD77C9")]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface IAddinHelper
{
    string GetPresentation();
    string GetString();
}

[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
[Guid("A523844E-1A41-4118-A0F0-FDFA7BCD77C9")]
[ComSourceInterfaces(typeof(IAddinHelper))]
public class AddinHelper : StandardOleMarshalObject, IAddinHelper

-, private AddinHelper _comAddinObject; ( [: InternalsVisibleTo ( "MyProject.Tests" )] , ).

-, , Powerpoint COM. , Office App.

, , COM.

Viola:

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: , , SO'r: Moq Interop Types: VS2012, VS2010?