C＃单元测试卡在COM对象上

Question

I am working on a project in C# and i have a piece of cod that work perfectly in main() but in tests the debugger get stuck on a COM object call and test can't pass that line.

This is the code:

    private ICMSDWorkset CMSWorkset;
    private ICMSDProject CMSProject;
    [TestMethod()]
    public void CMSConnector_EntityProviderTest()
    {
        string connectionString = @"PATH";

        CMSAPI capi = new CMSAPI();
        //capi.Init(connectionString, "USER", "Project name");
        Init(connectionString, "@SETUP", "iDB_P01");

        Terminate();
    }
    private void Init(String connectionString, string currentUser, string currentProject)
    {
        CMSWorkset = new CPLTWorkset() as ICMSDWorkset;

        CMSWorkset.Init("", "", connectionString);

        if (!CMSWorkset.IsInitialized())
            throw new ArgumentException(
                new StringBuilder().AppendFormat("")
                    .AppendFormat("initialization failed for connection string '{0}'", connectionString)
                    .ToString()
            );

        // set user
        ICMSDOwnCollection tmpColl = CMSWorkset.GetAllUsers() as ICMSDOwnCollection;
        CMSWorkset.SetCurrentUser(tmpColl.Item(currentUser));

        // set project as current in workset
        tmpColl = CMSWorkset.GetAllProjects() as ICMSDOwnCollection;
        CMSProject = tmpColl.Item(currentProject) as ICMSDProject;
        CMSWorkset.SetCurrentProject(CMSProject);

        if (!CMSWorkset.IsInitialized())
            throw new ArgumentException(
                new StringBuilder().AppendFormat("")
                    .AppendFormat("initialization failed for connection string '{0}', user '{1}' and project name '{2}'",
                        connectionString, currentUser, currentProject)
                    .ToString()
            );
    }

    public void Terminate()
    {
        // do the deallocations; mandatory
        CMSWorkset.Terminate();
        CMSWorkset = null;
    }

On test debugging when i press step forward and reach this line :

CMSWorkset = new CPLTWorkset() as ICMSDWorkset;

the debugger stop working, the test continue running but remains stuck on that line .No errors or exceptions are throw .

CPLTWorkset is a wrapper for a COM object.

I checked 'Native code debugging' as other mentions on questions related to COM objects but without success.

Did anyone have any idea why debugger can't handle that line ? or why that piece of cod work on main but not on tests ?

Thanks!

Answer 1

My first guess is that the code invoked by new CPLTWorkset() only works on a thread that is marked as a [STAThread] . Your Main method has this attribute, making the main thread a single threaded apartment thread, while the threads used by your unit testing framework are not.

Note that just calling Thread.SetAparatmentState may not fix this; when a thread is an STA thread, this also implies that an event loop is being pumped on it (eg in WinForms, Application.Run would be called). That is going to be difficult to achieve in a unit test unless you really know what you are doing.