Unreliable tests related to query counting

[Gavin Panella]

Something today, 2014-10-03, appears to have caused several tests to become unreliable:

maasserver.views.tests.test_nodes.NodeViewsTest.test_node_list_num_queries_is_independent_of_num_nodes
maasserver.views.tests.test_tags.TagViewsTest.test_view_tag_num_queries_is_independent_of_num_nodes
maasserver.api.tests.test_nodes.TestNodesAPI.test_GET_list_nodes_issues_constant_number_of_queries

I noticed the problem when trying to land https://code.launchpad.net/~allenap/maas/increase-do-configure-dhcp-timeout/+merge/237130. That implies that code in that branch is to blame, but it is a staggeringly simple branch and it's hard to see how it would make any difference. Still, the possibility remains.

I will be disabling these tests and marking them with XXX referencing this bug.

[Graham Binns (gmb)]

On Friday, 3 October 2014, Gavin Panella <email address hidden>
wrote:

> Public bug reported:
>
> Something today, 2014-10-03, appears to have caused several tests to
> become unreliable:
>
>
> maasserver.views.tests.test_nodes.NodeViewsTest.test_node_list_num_queries_is_independent_of_num_nodes
>
> maasserver.views.tests.test_tags.TagViewsTest.test_view_tag_num_queries_is_independent_of_num_nodes
>
> maasserver.api.tests.test_nodes.TestNodesAPI.test_GET_list_nodes_issues_constant_number_of_queries
>

I fear this might have been caused by my branch to add alerts when clusters
are disconnected; I saw this failure when I tried to land the branch, but
couldn't reproduce it locally (and it landed on the second attempt anyway).
Of course, it could be that there was already something going weird and I,
like you, am only seeing it thanks to cosmic providence.

The reason I suspect my branch is that it adds an extra query — fetching
all accepted clusters — to each request. Why that doesn't have a consistent
effect I don't know (I was too jetlagged to dig around and then hey! the
problem went away!).

Anyway, just thoughts. Can't test them right now, but maybe someone else
can.