You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: test_gem_resolver_api_set.rb
    path of file: ./repos/truffleruby/test/mri/tests/rubygems
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
require_relative "helper"

class TestGemResolverAPISet < Gem::TestCase
  def setup
    super

    @DR = Gem::Resolver
    @dep_uri = URI "#{@gem_repo}info/"
  end

  def test_initialize
    set = @DR::APISet.new

    assert_equal URI("https://index.rubygems.org/info/"),   
    
  def test_prefetch_cache
    spec_fetcher

    @fetcher.data["#{@dep_uri}a"] = "---\n1  \n"

    set = @DR::APISet.new @dep_uri

    a_dep = @DR::DependencyRequest.new dep("a"), nil
    b_dep = @DR::DependencyRequest.new dep("b"), nil

    set.prefetch [a_dep]

    @fetcher.data.delete "#{@dep_uri}a"
    @fetcher.data["#{@dep_uri}?b"] = "---"

    set.prefetch [a_dep, b_dep]
  end