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: tc_cell_style.rb
    path of file: ./repos/caxlsx/test/stylesheet
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'tc_helper'

class TestCellStyle < Minitest::Test
  def setup
    @item = Axlsx::CellStyle.new
  end

  def teardown; end

  def test_initialiation
    assert_nil(@item.name)
    assert_nil(@it
    
  def teardown; end

  def test_initialiation
    assert_nil(@item.name)
    assert_nil(@item.xfId)
    assert_nil(@item.builtinId)
    assert_nil(@item.iLevel)
    assert_nil(@item.hidden)
    assert_nil(@item.customBuiltin)
  end

  def test_name
    assert_raises(ArgumentError) { @item.name = -1 }
    refute_raises { @item.name = "stylin" }
    assert_equal("stylin", @item.name)
  end

  def test_xfId
    assert_raises(ArgumentError) { @item.xfId = -1 }
    refute_raises { @item.xfId = 5 }
    assert_equal(5, @item.xfId)
  end

  def test_builtinId
    assert_raises(ArgumentError) { @item.builtinId = -1 }
    refute_raises { @item.builtinId = 5 }
    assert_equal(5, @item.builtinId)
  end

  def test_iLevel
    assert_raises(ArgumentError) { @item.iLevel = -1 }
    refute_raises { @item.iLevel = 5 }
    assert_equal(5, @item.iLevel)
  end

  def test_hidden
    assert_raises(ArgumentError) { @item.hidden = -1 }
    refute_raises { @item.hidden = true }
    assert(@item.hidden)
  end

  def test_customBuiltin
    assert_raises(ArgumentError) { @item.customBuiltin = -1 }
    refute_raises { @item.customBuiltin = true }
    assert(@item.customBuiltin)
  end
end