fixup! Add a test suite to make sure we properly count people related to a place.
Use the context to check number of members

This will give a more robust test of whether the correct number of
people are found associated with each organisation.
Check the context rather than the absence of text in the page

Check that particular string isn't present in the generated HTML might
fail for many reasons unrelated to a miscount, which might be difficult
to track down - instead check that the length of
context['related_people'] is 0.
Fix the test for total number of people associated with a Place

Perhaps "fix" isn't the right word, but this makes the test match the
current intent: as the code is written at the moment, the count of
people associated with the place contains every person with a current
position associated with this Place. This might look confusing, since
some of these people won't be findable through this page, but that's
probably another bug (either to change that displayed count, or to
include links to "other associated people").