Unit tests can run into trouble when tasks that create OperationContexts are run inline because the testing infrastructure may have already established an OperationContext and a Client cannot have more than one OperationContext associated with it.

This is a problem for ShardServerCatalogCacheLoader unit testing, where the unit test ShardServerCatalogCacheLoaderTest inherits from ShardServerTestFixture that provides an operation context. Then the ShardServerCatalogCacheLoader destructor runs join on it's thread pool, which contains tasks that require and create OperationContexts.