module ActiveSupport::Testing::ConstantStubbing

divergent stubbing will trample on each other.
(like separate test suites running in parallel) that all depend on the same constant, it's possible
Note: Stubbing a const will stub it across all threads. So if you have concurrent threads

end
assert_equal 1, SOME_CONST
stub_const(object, :SOME_CONST, 1, exists: false) do

you can do so by passing `exists: false`.
If the constant doesn't already exists, but you need it set for the duration of the block

warnings from being thrown, and ensures that the old value is returned after the test has completed.
Using this method rather than forcing World::List::Import::LARGE_IMPORT_THRESHOLD = 5000 prevents

assert_equal 5000, World::List::Import::LARGE_IMPORT_THRESHOLD

end
assert_equal 1, World::List::Import::LARGE_IMPORT_THRESHOLD
stub_const(World::List::Import, :LARGE_IMPORT_THRESHOLD, 1) do
# World::List::Import::LARGE_IMPORT_THRESHOLD = 5000

Changes the value of a constant for the duration of a block. Example:

def stub_const(mod, constant, new_value, exists: true)
  if exists
    begin
      old_value = mod.const_get(constant, false)
      mod.send(:remove_const, constant)
      mod.const_set(constant, new_value)
      yield
    ensure
      mod.send(:remove_const, constant)
      mod.const_set(constant, old_value)
    end
  else
    if mod.const_defined?(constant)
      raise NameError, "already defined constant #{constant} in #{mod.name}"
    end
    begin
      mod.const_set(constant, new_value)
      yield
    ensure
      mod.send(:remove_const, constant)
    end
  end
end