Application.Current - Null for unit tests.

Question

I have some methods in the code base that rely on Application.Current.Dispatcher.Invoke ... to make sure everything works in the GUI thread. I'm currently trying to write unit tests for these methods, but (as expected) Application.Current is null, so I get a NullReferenceException.

I tried to run the test tests in my own AppDomain, as suggested here: http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/786d5c06-0511-41c0-a6a2-5c4e44f8ffb6/

But Application.Current is still null when I do this. Shouldn't I launch AppDomain for Application.Current for me? Why is it still null?

My code: Base class:

[TestClass()] [Serializable] public class UnitTest { protected void ExecuteInSeparateAppDomain(string methodName) { AppDomainSetup appDomainSetup = new AppDomainSetup(); appDomainSetup.ApplicationBase = Environment.CurrentDirectory; AppDomain appDomain = AppDomain.CreateDomain(methodName, null, appDomainSetup); try { appDomain.UnhandledException += delegate(object sender, UnhandledExceptionEventArgs e) { throw e.ExceptionObject as Exception; }; UnitTest unitTest = appDomain.CreateInstanceAndUnwrap(GetType().Assembly.GetName().Name, GetType().FullName) as UnitTest; MethodInfo methodInfo = unitTest.GetType().GetMethod(methodName, BindingFlags.NonPublic | BindingFlags.Instance); if (methodInfo == null) { throw new InvalidOperationException(string.Format("Method '{0}' not found on type '{1}'.", methodName, unitTest.GetType().FullName)); } try { methodInfo.Invoke(unitTest, null); } catch (System.Reflection.TargetInvocationException e) { throw e.InnerException; } } finally { AppDomain.Unload(appDomain); } } } 

The calling unit test (contained in a class that inherits from UnitTest):

 [TestMethod()] public void QualifierViewModel_FlagsAndLoadDatasets() { ExecuteInSeparateAppDomain("TestLoadDataSets"); } 

Answer 1

So at the moment I have an unpleasant workaround. I basically moved all the tests that test the methods that use Application.Current to one test (so that they will all be in the same thread) and will call a new application ().

Strong code:

 [TestClass] public class IntegrationTests { private CedarFile testCedarFile; /// <summary> /// This test tests methods that utilize Application.Current. /// They all have to be in the same test because they must run on the same thread to use the Application instance. /// </summary> [TestMethod] public void IntegrationTests_All() { new Application(); QualifierViewModel_FlagsAndLoadDatasets(); CurrentFilesViewModel_AddCedarFile(); CurrentFilesViewModel_AddCedarFileReadOnly(); } ... the private methods to test ... } 

Answer 2

This workaround works for me:

 [TestClass] public class MockAppTests { private static Application application = new Application() { ShutdownMode= ShutdownMode.OnExplicitShutdown }; } [TestClass] public class IntegrationTests : MockAppTests { [TestMethod] public void MyTest() { //test } } 

Answer 3

Try removing the Serializable attribute and instead derive the UnitTest class from MarshalByRefObject .