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_assembler.rb
    path of file: ./repos/ruby/test/ruby/rjit
    
    the code of the file until where you have to start completion: require 'test/unit'
require_relative '../..
    
    def test_sub
      asm = Assembler.new
      asm.sub(:rax, 8)    # SUB r/m64, imm8 (Mod 11: reg)
      asm.sub(:rax, :rbx) # SUB r/m64, r64 (Mod 11: reg)
      assert_compile(asm, <<~EOS)
        0x0: sub rax, 8
        0x4: sub rax, rbx
      EOS
    end