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_proc.rb
    path of file: ./repos/ruby.wasm/packages/npm-packages/ruby-wasm-wasi/test/unit
    
    the code of the file until where you have to start completion: require "test-unit"
require "js"

class JS::TestProc < Test::Unit::TestCase
  def test_with_js_call
    function_to_call = JS.eval("return { a: (callback) => { callback(1) } }")
    b = n
    
  def test_store_in_js
    function_to_call = JS.eval(<<~JS)
      let callback;
      return {
        set: (c) => { callback = c },
        invoke: () => { callback(1) }
      }
    JS
    b = nil
    function_to_call.call(:set) { |a| b = a.to_i }
    function_to_call.call(:invoke)
    assert_equal 1, b
  end