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_cstr.rb
    path of file: ./repos/ruby/test/-ext-/string
    
    the code of the file until where you have to start completion: # frozen_string_literal: false
require 'test/unit'
require "-test-/string"

class Test_StringCStr < Test::Unit::TestCase
  Bug4319 = '[ruby-dev:43094]'

  def 
    
  def assert_wchars_term_char(str)
    result = {}
    WCHARS.map do |enc|
      s = Bug::String.new(str.encode(enc))
      yield s
      c = s.cstr_term_char
      result[enc] = c if c
    end
    assert_empty(result)
  end