Use supported rspec syntax (expect, not should)

This prevents the warning:
  Using `should` from rspec-expectations' old `:should` syntax without explicitly enabling the syntax is deprecated.
  Use the new `:expect` syntax or explicitly enable `:should` instead.

There is still a similar warning from rspec-mocks about .stub(), but I
think that will evaporate if we clean up the Gemfile.

Rspec is moving away from .should because it requires monkey-patching
the base Object class, which can produce extremely phantom errors.
Test was passing anyway, which means it is not pending

Possible copy/paste error.
Pure whitespace format correction