Code review comment for lp:~alan-griffiths/mir/is-NullWindowManager-better-than-GenericShell

I'm looking at the failure...

5: [ FAILED ] 13 tests, listed below:
5: [ FAILED ] ServerDisconnect.is_detected_by_client
5: [ FAILED ] ServerDisconnect.doesnt_stop_client_calling_API_functions
5: [ FAILED ] ServerDisconnect.causes_client_to_terminate_by_default
5: [ FAILED ] ServerStartup.creates_endpoint_on_filesystem
5: [ FAILED ] ServerStartup.after_server_sigkilled_can_start_new_instance
5: [ FAILED ] UnresponsiveClient.does_not_hang_server
5: [ FAILED ] CustomInputDispatcher.receives_input
5: [ FAILED ] CustomInputDispatcher.gets_started_and_stopped
5: [ FAILED ] CustomInputDispatcher.receives_focus_changes
5: [ FAILED ] FocusSelection.when_surface_created_shell_is_notified_of_session
5: [ FAILED ] FocusSelection.when_surface_created_input_focus_is_set
5: [ FAILED ] BespokeDisplayServerTestFixture.the_shell_surface_configurator_is_notified_of_attribute_changes
5: [ FAILED ] BespokeDisplayServerTestFixture.the_shell_surface_configurator_may_interfere_with_attribute_changes

... but not only can I reproduce it locally, I can reproduce it on trunk.