WF has a configuration property: MaxSimultaneousWorkflows - other than building a custom test app or workflow, how can you verify that the property is working?
The reason not to build a custom test app or workflow is that it doesn't tell you about the workflow that I am actually trying to verify.
Update The reason to verify it is to make sure it is working as Microsoft documented it when run with the workflows that will be run in production, as a way to verify there are no bugs in WF setting.
Maybe you can explain why you need to check MaxSimultaneousWorkflows?
The purpose of the MaxSimultaneousWorkflows setting is that the default workflow scheduler uses no more than the specified number of threads for simultaneous workflow activity execution. So you can start as many worklfows as you like but only the specified number will be executing at the same time. The workflow runtime, or more accurately the DefaultWorkflowSchedulerService, does this.
So your question makes me wonder of you are trying to unit test the DefaultWorkflowSchedulerService?