Specific importer tests are poorly scoped

[kimadactyl]

Description

Bug fixing things to do with the importer is tricky as there's a lot of tests that look a lot to me like magic number assertations. For example, this test asserts that there should be 15 events - why?

PlaceCal/test/jobs/calendar_importer/calendar_importer_task_test.rb

Line 132 in 97c5c25

assert_equal 15, created_events.count

An example of why this is confusing is that if I remove the ! here, the event count changes from 15 to 17. I can't meaningfully reason about why.

PlaceCal/app/jobs/calendar_importer/parsers/ld_json.rb

Line 116 in 4ea8af5

events.select! { |ev| ev.valid? && ev.in_future? }

I think overall we need smaller and more specific unit tests for each stage of the process rather than these monolithic end to end ones.

Motivation

Importer logic is hard to reason about and test values seem arbritrary. This is a good recipe for introducing a lot of magic number bugs, and doesn't help us understand more about the code.