I download the sample Windows Server AppFabric Workflow Services Demo - Contoso HR and ran the tests. All tests passed. The test project uses Microsoft.Activities.UnitTesting (ver 2.0.0.13).
I use NuGet to install the latest Microsoft.Activities.UnitTesting (ver 2.0.6.9).
host.WaitForHostClosed() will always return false and thus Assert.IsTrue(host.WaitForHostClosed()); fails.

Please help to fix it. Thanks.
Suggest to add unit tests for host.Close() and host.WaitForHostClosed() :)

FYI, I am using Microsoft Visual Studio Premium 2012 Version 11.0.50727.1 RTMREL