def run(situation)
      situation.setup(&definition)
      [:setup]
    rescue StandardError => e
      [:setup_error, e]
    end
Calls {Riot::Situation#setup} with the predefined block at {Riot::Context} run-time. Though this is
like every other kind of {Riot::RunnableBlock}, +run+ will not return a meaningful state, which means
the reporter will likely not report anything.

@param [Riot::Situation] situation the situation for the current {Riot::Context} run
@return [Array<Symbol>] array containing the evaluation state