Silence test warnings #15572
Description
Problem
Adding t.warning = true to each test block in the Rakefile generates over 20,000 warnings from a rake test:all
Proposed Solution
Silence these, and have the warnings turned on by default.
Acceptance Criteria
rake test:all doesn't issue any warnings with t.warning = true enabled.
Not Required
This doesn't need to (and indeed almost certainly should not) happen in a single PR. Multiple small PRs, each silencing a single class of error, is the way to go.