remove dynamic class creation where not needed

[NullVoxPopuli]

Purpose

Part n+1 in a long-running series of test improvements. This particular episode is to discourage people from (or at least not show them how to) dynamically creating classes for testing when they don't need to be dynamically created.

Changes

any class-level SubClass = Class.new(SuperClass) was converted to class SubClass < SuperClass; end

Caveats

None

Related GitHub issues

#1848 (comment)

Additional helpful information

Step next will be renaming tests from

def test_method_whatever to test 'this is what is being tested' do

[mention-bot]

@NullVoxPopuli, thanks for your PR! By analyzing the annotation information on this pull request, we identified @beauby, @joaomdmoura and @domitian to be potential reviewers

[bf4]

@NullVoxPopuli looks good. Just two style issues:

Offenses:
test/fixtures/poro.rb:91:7: C: Style/ClassAndModuleChildren: Use nested module/class definitions instead of compact style.
class Spam::UnrelatedLink < Model; end
      ^^^^^^^^^^^^^^^^^^^
test/fixtures/poro.rb:279:7: C: Style/ClassAndModuleChildren: Use nested module/class definitions instead of compact style.
class Spam::UnrelatedLinkSerializer < ActiveModel::Serializer
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[NullVoxPopuli]

@bf4 fixed. Thanks!